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Bridging climate science, citizens, and policy


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Continuing a Theme

The Nordhaus & Shellenberger piece certainly has kicked up a lot of dust, including from someone whose work I normally enjoy.  Tom Toles issued his own ranting screed at the Washington Post yesterday.  It includes most of the same over-the-top grousing about the N&S piece as other writers.  But it includes a couple of things I’d like to highlight for additional discussion.

The ‘concern’ is that as a tactic it can ‘backfire’ and not win over conservatives to climate change action. Not win over conservatives! The article doesn’t place ALL the blame on faulty environmentalist tactics. It pauses to include what may be the most understated disclaimer in history: “Other factors contributed. Some conservatives and fossil-fuel interests questioned the link between carbon emissions and global warming.” Some! Really???

At what point will people realize that if we nullify conservative’s work against climate action, then the very thing Toles and others claim to care about so deeply will finally happen: widespread and robust climate action?!  No, Tom is right.  We should continue the same strategies that failed for 30+ years, because one day, gosh darn it, they’ll magically work.  It’s quite simple really: identify and work via values and tactics that resonate with conservatives to achieve the same goal that working via different values and tactics that resonate with liberals.  This is where tribalism rears its ugly head big time.  Instead of recognizing inherent worldview differences and expending effort to talk to conservatives differently than liberals, it is much easier to shut your brain down and scream about how conservatives are “others” and should therefore be banned from all decision-making.  What a wonderful strategy!  Obviously it’s worked since so many conservatives are voting for carbon taxes and setting up subsidies for renewable energy and … that’s right, none of that is happening, is it?

N&S pointed out that many environmentalists work against their stated goals by purposefully shutting out 1/3 of the population.  That doesn’t sit well with Toles or Romm or many others.

Here is the second thing Toles writes that irks me:

If environmentalists aren’t careful, it says, sufficient support for an adequate policy response might go away. Go away! As though it was ever even close to being there in the first place. They cite Al Gore’s 2006 ‘Inconvenient Truth’ as contributing to backlash and division. Do they think no one has any memory whatsoever? Let me remind those who don’t. Before “Inconvenient Truth’ there was close to ZERO widespread public concern about climate change.

How close to ZERO was there, Tom?  Let’s check the first thing that comes up when I Google search ‘global warming polling 1980′:

 photo GlobalWarmingPollingGallup1989-2013_zpsf586fd1f.gif

Well, would you look at that – somebody polled Americans for decades now – who would have thought?  It turns out that 50-72% of Americans worrying a great deal or a fair amount is close to ZERO in Tom’s world.  That’s enlightening.  Gore released “An Inconvenient Truth” in early 2006.  In Gallup polling, worry jumped from 51% in 2004 to 62% in 2006 and 66% in 2008.  So yes, Truth likely brought American’s attention back to the issue in a way that other efforts did not.  Note however a couple of things this time series shows us: support was higher in 1999 and 2000 than 2008.  So Truth wasn’t the most effective strategy.  Also, worry post-2008 fell back to 2004 levels: 51%.  Worry was falling in 2009 – when Waxman and Markey were writing their cap-and-trade legislation – through 2010 – when the legislation failed to pass Congress.  That was despite having a Democratic President and a Democratic-led House and Senate.  That combination will not repeat itself any time soon.  So what should liberals do?  Find alternate tactics to motivate conservatives instead of denigrating and alienating them?  That sounds crazy to me.

Gallup’s page has plenty of other interesting results to chew over.  I will include one more in this post for illustrative purposes because it gets at the heart of what N&S really wrote about.  Gallup started asking in 1997 whether people thought global warming was a threat in their lifetime.  Guess what the majority answer was.  That’s right: most people said “no”.  Most people (50%-69%) hold this belief at the same time they believe that global warming is real, that human activities cause it, and that news reports on it are correct, if not underestimated.

What does that mean?  It means that people view the problem as a distant threat that will impact others before Americans.  There is scientific truth behind this belief.  The first reports of impacts were on Asians and Africans.  Those same populations will continue to be disproportionately affected in the coming decades, as the IPCC AR5 reported this year.

N&S’s post was an attempt to change this perception.  If scientists employ “communications approaches that take account of individuals’ personal points of reference (e.g., based on an understanding and appreciation of their values, attitudes, beliefs, local environment, and experiences) are more likely to meaningfully engage individuals with climate change,” more people are likely to view climate change as a direct threat to their own lives.  If that happens, support for climate action will break through traditional barriers.  But I guess Toles, Romm, and others aren’t really interested in that.  They’re interested in this topic on ideological grounds: so long as liberals beat conservatives and people with slightly different worldviews, they’re happy.


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Climate News & Opinion Links – March 26 2014

I’ve collected a number of interesting climate and energy related news releases, stories, and opinion pieces in the past couple of weeks.  In no particular order:

The only way we will take large-scale climate action is if there are appropriate price signals in markets – signals that reach individual actors and influence their activities.  One step in the right direction was phasing out federal subsidies for high-risk coastal properties’ flood insurance policies, as Congress did in 2012.  This had the expected effect of increasing premiums for policy holders.  Unsurprisingly, people don’t want to pay more to live in their high-risk homes.  So they complained to their representatives, who responded by passing new legislation … reinstating government subsidies.  Taxpayers across the country are shoveling good money after bad for a select handful of wealthy people to build without mitigating risk to their homes or paying the true economic costs of their lifestyle decisions.  We will pay for them to rebuild again and again (remember: sea levels will rise for centuries) unless we as a society decide to stop.

Tesla is entering the energy industry.  This could be a game changer in terms of home solar energy and electric vehicles, no matter how Tesla comes out in the long-term.

20 years of IPCC effort and “achievement”.  With no robust international climate agreement after 20 years’ of work, I have a hard time accepting the claim the IPCC has achieved much of anything except an excessive bureaucracy and huge reports that few people read.

News that’s not really news: Asia will be among those hardest hit by climate change.  This isn’t a new result, but something that the IPCC’s WGII report will report on with increased confidence in 2014 versus 2007 (see above statement).  The number of people living close to coasts in Asia dwarf the total population of countries who historically emitted the most greenhouse gases.  That was true in 2007 and will be true in the future.  It will take a generation or more before effects on developed nations generate widespread action.

New research (subs. req’d) indicates ice gains in Antarctica’s Ross Sea will reverse by 2050.  Recent temperature and wind current patterns will shift from their current state to one that encourages rapid ice melt, similar to what the Arctic experienced in the past 20 years or so.

An El Nino might be developing in the tropical Pacific.  The anomalous heat content traveling east via an Equatorial Kelvin Wave rivals that of the 1997-1998 El Nino, which was the strongest in recorded history.  Earlier this month, NOAA’s Climate Prediction Center issued an El Nino Watch, citing a 50% probability that an El Nino would develop in summer or fall 2014, based in part on projections such as Columbia University’s.  El Nino is the warm phase of the ENSO phenomenon.  Warm ocean waters move from the western to eastern Pacific, affecting global atmospheric circulations.  Related to science policy, one result of Congress’ austerity approach to the economy is  monitoring buoys’ degradation in the Pacific Ocean.  NOAA helped deploy a widespread network of buoys following the 1982-1983 El Nino which helped track the progress of the 1997-1998 El Nino with greatly improved fidelity.  That network is operating at less than 75% of its designed capacity, hampering observations.  If we can’t observe these impactful events, we can’t forecast their effects.  This negatively impacts business’ and peoples’ bottom line.

Finally, I want to make some observations regarding goings-on within the climate activist community.  Vocal critics recently spent a lot of energy on hit pieces, this being only one example (poorly written with little on science, heavy on “he-saids”, with an overdose of personal insults and vindictive responses to anyone who didn’t agree with the piece, including my comments).  These writings demonstrate something rather simple to me: if you do not agree with 100% of what the activist consensus is, you’re no better than people the activists label ‘deniers’.  Additionally, the their argument is absurd: social scientists have no business analyzing climate data or commenting on activist’s claims.  Why is this absurd?  Because they simultaneously hold the contradictory belief that physical scientists should have exclusive input and decision-making power over climate policy (a social creation).  Furthermore, implicit in their messaging is social scientists don’t have the right kind of expertise to participate in “serious” discussions.  These efforts to deligitimize someone they don’t believe should participate (how very elitist of them) is reminiscent of efforts by many in the Republican party to deligitimize Barack Obama’s presidency simply because of his race.  Nothing is gained and much is lost by these efforts.  How does this advance the climate discussion to people not currently involved, which will need to happen if we are to ever take any kind of large-scale climate action?

Additional lack of critical thought is found in this post, mostly in this penultimate paragraph:

I’ve said before that I think people can believe what they want, as long as they don’t try to act on those beliefs in a way that interferes with others’ lives. When they deny the reality of global warming, and preach it to their flock, that’s exactly what they’re doing (incidentally, a large fraction of Americans believe to some extent the Bible is literally true).

The very same complaint is made by the people the author derides in this paragraph and post but in reverse and it’s one of the biggest reasons why we’ve taken so little climate action.  The author’s condescension is plainly evident for those who don’t believe exactly as he does. Instead of trying to reach out to people with different beliefs (and underlying value systems), he takes the lazy route and spends time insulting them.  Have you ever believed in something you didn’t previously after someone insulted you?  No, it’s an absurd and self-defeating strategy.  These basic problems underlie most climate change discussions and people retrench their positions instead of trying to step into other’s shoes.  I’m not sure how much this has to change before we undertake more widespread and effective climate mitigation strategies.


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IPCC’s Fifth Assessment Report – Working Group I – Released Today

My Twitter feed has heavy volume today because of the IPCC’s Fifth Assessment Report (AR5) Working Group I’s (WGI) Summary for Policymakers official release.

I have waited since 2007 (when they released AR4) for this report’s issuance.  I read most of the AR4′s WGI report (1000 pages long).  Since it’s release, I have read hundreds of climate-related journal articles so I could stay current on the latest research.  I have also read some of AR4′s WGII report, dozens of social science journal papers and books because it became clear to me after the AR4 WGI report that there was no significant problem with the science.  As a scientist, I realized that the state of climate science hasn’t changed appreciably for decades.  The same top-level messages of the First Assessment Report remain in place today.  The AR5 WGI report primarily provides more confidence in the reported numbers.  Detail changes are relatively minor compared to the knowledge body that existed in 1990.  Scientists will continue to work on important items such as mechanisms behind deep ocean heat uptake and cryosphere dynamics.  They need to better model Important feedback processes because of their nonlinearities.  But the science, by and large, settled long ago.

What remains is our handling of that science, which is where social science knowledge comes in.  The difference between acting today to provide cheap, reliable energy to the 1 billion people on Earth who currently have no such access with clean energy versus dirty energy is monumental.  Prior to that, we need a reconciliation between believers and skeptics.  Nobody should browbeat anyone else in a conversion effort.  Instead, we need to identify solution pathways which acknowledge multiple worldviews.  Those pathways exist but the status quo is awfully powerful within today’s systems.  Changing from the status quo will not be easy, but it will be fruitful.  Unfortunately, that very same Twitter feed puts that status quo on display daily; the more so when the IPCC issues a comprehensive science report.  Why do the same climate scientists that demand others believe a particular stance from peer-reviewed physical science articles discount a particular stance from peer-reviewed social science articles?  Should we trust experts, or not?  The reason is tribalism.  Tribalism runs rampant on Twitter and too many people think if they shout a little louder every day that eventually everyone will hear and agree with them, despite years of evidence to the contrary.

There is plenty to write about and discuss within the IPCC AR5 summary.  I will do so as time permits.  I do want to pass along a good article written by Andrew Revkin (the most salient part is at the end).  My own research is climate science-based, but I am also working on a social science aspect in order to make the physical science results meaningful to policymakers.


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Energy Generation Now & in the Future

I finished my last post with an important piece of data.  Out of 100 quads of energy the US generates every year, the vast majority of it (83%) comes from fossil fuel sources – sources that emit greenhouse gases when we burn them.  The same is true for the vast majority of other countries, and therefore for the global portfolio as well.  Here is a graphic showing global energy consumption distribution by fuel type from 1990 through 2010 and into the future:

 photo EIA-WorldEnergyConsumptionbyfueltype1990-2040_zps8d8ae886.png

Figure 1. Global fuel-type energy consumption, 1990-2040 (EIA 2013 Energy Outlook).

The global picture is somewhat different from the US picture: liquids’ energy (e.g., oil) exceed coal energy, which exceed natural gas.  All three of these carbon-intensive energy sources, which power our developed, high-wealth lifestyles, greatly exceed renewables (which hydropower dominates), which exceeds nuclear.  It is these type of energy forecasts that lead to the suite of IPCC emissions pathways:

 photo IPCCAR5RCPScenarios_zps69b8b0d5.png

Figure 2. IPCC Fifth Assessment Report Representative Concentration Pathway (RCP) CO2-eq concentrations.

Note that our current emissions trajectory more closely resembles the RCP8.5 pathway (red) than the other pathways.  This trajectory could lead to a 1000+ ppm CO2-eq concentration by 2100, or 2.5X today’s concentration value.  Stabilizing global temperature increases at less than 2C by 2100 requires stabilizing CO2-eq concentrations below 450 and quickly decreasing, which is best represented by the RCP2.6 pathway above (green).  This pathway is technologically impossible to achieve as of today.  The only way to make it possible is to invest in innovation: research, development, and global deployment of low-carbon technologies.  We are not currently doing that investment; nor does it look likely we will in the near future.

Let’s take a further look at the recent past before we delve further into the future.  Environmental and renewable energy advocacy groups tout recent gains in renewable energy deployment.  We should quietly cheer such gains because they are real.  But they are also miniscule – far too little deployment at a time when we need exclusive and much wider deployment of renewable energy globally to shift our emissions pathway from RCP8.5 to RCP2.6.  Here is a graphic showing global use of coal in the past 10+ years:

 photo WorldCoalConsumption-2001-2011_zps68aea439.jpg

Figure 3. Global coal use in million tonnes of oil-equivalent 2001-2011 (Grist).

Climate and clean energy advocates like to report their gains in percentage terms.  This is one way of looking at the data, but it’s not the only way.  For instance, coal usage increased by 56% from 2001 to 2011.  This is a smaller percentage than most renewable energy percentage gains in the same time period, but the context of those percentages is important.  As you’ll see below, renewable energy gains really aren’t gains in the global portfolio.  The above graph is another way to see this: if renewable energy gains were large enough, they would replace coal and other fossil fuels.  That’s the whole point of renewable energy and stabilizing carbon emissions, right?  If there is more renewable energy usage but also more coal usage, we won’t stabilize emissions.  Here is another way of looking at this statement:

 photo GlobalEnergyConsumption-Carbon-FreeSources1965-2012_zps1a06c9a0.png

Figure 4. Global Energy Consumption from Carbon-Free Sources 1965-2012 (Breakthrough).

Carbon-free energy as a part of the total global energy portfolio increased from 6% in 1965 to 13% in the late 1990s.  This is an increase of 200% – which is impressive.  What happened since the 1990s though?  The proportion was actually smaller in 2011 than it was in 1995 in absolute terms.  At best, carbon-free energy proportions stagnated since the 1990s.  Countries deployed more carbon-free energy in that time period, but not enough to increase their proportion because so much new carbon energy was also deployed.  What happened starting in the 1990s?  The rapid industrialization of China and India, predominantly.  Are developing countries going to stop industrializing?  Absolutely not, as Figure 1 showed.  It showed that while renewable energy consumption will increase in the next 30 years, it will likely do so at the same rate that natural gas and liquids will.  The EIA projects that the rate of increase of coal energy consumption might level off in 30 years, after we release many additional gigatonnes of CO2 into the atmosphere, ensuring that we do no stabilize at 450 ppm or 2°C.

Here is the EIA’s projection for China’s and India’s energy consumption in quads, compared to the US through 2040:

 photo EIA-EnergyConsumption-US-CH-IN1990-2040_zps70837e84.png

Figure 5. US, Chinese, and Indian energy consumption (quads) 1990-2040 (EIA 2013 Energy Outlook).

You can see the US’s projected energy consumption remains near 100 quads through 2040.  China’s consumption exceeded the US’s in 2009 and will hit 200 quads (2 US’s!) by 2030 before potentially leveling off near 220 quads by 2040.  India’s consumption was 1/4 the US’s in 2020 (25 quads), and will likely double by 2040.  Where will an additional 1.5 US’s worth of energy come from in the next 30 years?  Figure 1 gave us this answer: mostly fossil fuels.  If that’s true, there is no feasible way to stabilize CO2 concentrations at 450 ppm or global mean temperatures at 2°C.  That’s not just my opinion; take a look at a set of projections for yourself.

Here is one look at the future energy source by type:

 photo GlobalEnergyByType-2013ProjectionbyBNEF_zps36f9806f.jpg

Figure 6. Historical and Future Energy Source by Type (BNEF).

This projection looks rosy doesn’t it?  Within 10 years, most new energy will come from wind, followed by solar thermal.  But look at the fossil fuels!  They’re on the way out.  The potential for reduced additional fossil fuel generation is good news.  My contention is that it isn’t happening fast enough.  Instead of just new energy, let’s look at the cumulative energy portfolio picture:

 photo GlobalEnergyTotalByType-2013ProjectionbyBNEF_zps88331d51.jpg

Figure 7. Historical and Future Total Energy Source by Type (BNEF).

This allows us to see how much renewable energy penetration is possible through 2030.  The answer: not a lot, and certainly not enough.  2,000 GW of coal (>20% of total) remains likely by 2030 – the same time when energy experts say that fossil fuel use must be zero if CO2 concentrations are to remain below 450 ppm by 2100.  But coal isn’t the only fossil fuel and the addition of gas (another 1,700 GW) and oil (another 300 GW) demonstrates just how massive the problem we face really is.  By 2030, fossil fuels as a percentage of the total energy portfolio may no longer increase.  The problem is the percentages need to decrease rapidly towards zero.  Nowhere on this graph, or the next one, is this evident.  The second, and probably more important thing, about this graph to note is this: total energy increases at an increasing rate through 2030 as developing countries … develop.

 photo EIA-WorldEnergyConsumptionbyfueltype1990-2040_zps8d8ae886.png

Figure 8. Global fuel-type energy consumption, 1990-2040 (EIA 2013 Energy Outlook).

The EIA analysis agrees with the BNEF analysis: renewables increase through 2030.  The EIA’s projection extends through 2040 where the message is the same: renewables increase, but so do fossil fuels.  The only fossil fuel that might stop increasing is the most carbon intensive – coal – and that is of course a good thing.  But look at the absolute magnitudes: there could be twice as many coal quads in 2040 as there were in 2000 (50% more than 2010).  There could also be 50% more natural gas and 30% more liquid fuels.  But the message remains: usage of fossil fuels will likely not decline in the next 30 years.  What does that mean for CO2 emissions?

 photo EIA-WorldEnergy-RelatedCO2Emissionsbyfueltype1990-2040_zps417bffc4.png

Figure 9. Historical and projected global carbon dioxide emissions: 1990-2040 (EIA 2013 Energy Outlook).

Instead of 14 Gt/year (14 billion tonnes per year) in 2010, coal in 2040 will emit 25 Gt/year – almost a doubling.  CO2 emissions from natural gas and liquids will also increase – leading to a total of 45 GT/year instead of 30 GT/year.  The International Energy Agency (IEA) estimated in 2011 that “if the world is to escape the most damaging effects of global warming, annual energy-related emissions should be no more than 32Gt by 2020.”  The IEA 2012 World Energy Outlook Report found that annual carbon dioxide emissions from fossil fuels rose 1.4 percent in 2012 to 31.6 Gt.  While that was the lowest yearly increase in four years, another similar rise pushes annual emissions over 32Gt in 2014 – six years ahead of the IEA’s estimate.  Based on the similarity between our historical emissions pathway and the high-end of the IPCC’s AR4 SRES scenarios (see figure below), 2°C is no longer a viable stabilization target.

 photo CO2_Emissions_IPCC_Obs_2012_zpsd3f8cb8f.jpg

Figure 10. IEA historical annual CO2 emissions and IPCC AR4 emissions scenarios: 1990-2012 (Skeptical Science).

The A2 pathway leads to 3 to 4°C warming by 2100.   Additional warming would occur after that, but most climate science focus ends at the end of this century.  A huge caveat applies here: that warming projection comes from models that did not represent crysophere or other processes.  This is important because the climate system is highly nonlinear.  Small changes in input can induce drastically different results.  A simple example of this is a change in input from 1 to 2 doesn’t mean a change in output from 1 to 2.  The output could change to 3 or 50, and we don’t know when the more drastic case will take place.  Given our best current but limited understanding of the climate system, 3 to 4°C warming by 2100 (via pathway A2) could occur.  Less warming, given the projected emissions above, is much, much less likely than more warming than this estimate.  Policy makers need to shift focus away from 2°C warming and start figuring out what a 3 to 4°C warmer world means for their area of responsibility.  Things like the timing of different sea level rise thresholds and how much infrastructure should we abandon to the ocean?  Things like extensive, high-magnitude drought and dwindling fresh water supplies.  These impacts will have an impact on our lifestyle.  It is up to us to decide how much.  The graphs above and stories I linked to draw this picture for me: we need to change how we approach climate and energy policy.  The strategies employed historically were obviously inadequate to decarbonize at a sufficient rate.  We need to design, implement, and evaluate new strategies.


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February 2013 CO2 Concentrations: 396.80 ppm

During February 2013, the Scripps Institution of Oceanography measured an average of 396.80ppm CO2 concentration at their Mauna Loa, Hawai’i’s Observatory.

This value is a big deal.  Why?  Because not only is 396.80 ppm the largest CO2 concentration value for any February in recorded history, it is the largest CO2 concentration value in any month in recorded history.  More on that below.  This year’s February value is 3.37 ppm higher than February 2012′s!  Most month-to-month differences are between 1 and 2 ppm.  This jump of 3.37 ppm is very high.  Of course, the unending trend toward higher concentrations with time, no matter the month or specific year-over-year value, as seen in the graphs below, is more significant.

Let’s get back to that all-time high concentration value.  The yearly maximum monthly value normally occurs during May. Last year was no different: the 396.78ppm concentration in May 2012 was the highest value reported last year and, prior to this moth, in recorded history (neglecting proxy data).  We can expect March, April, and May of this year to produce new record values.  I wrote the following last month:

If we extrapolate last year’s maximum value out in time, it will only be 2 years until Scripps reports 400ppm average concentration for a singular month (likely May 2014; I expect May 2013′s value will be ~398ppm).  Note that I previously wrote that this wouldn’t occur until 2015 – this means CO2 concentrations are another climate variable that is increasing faster than experts predicted just a short couple of years ago.

For the most part, I stand by that prediction.  But actual concentration increases might prove  me wrong.  Here is why: the difference in CO2 concentration values between May 2012 and February 2012 was 3.13 ppm (396.78 – 393.65).  If we do the simplest thing and add that same difference to February’s value, we get 399.93 ppm.  That is awfully close to 400 ppm.  A more robust approach would be to add an average value – say the annual growth rate from the past 3, 5, or 10 years.  Over those time periods, the average differences are 2.31 ppm, 2.08 ppm, and 2.08 ppm.  So it’s probably safe to assume a growth of at least 2 ppm, which is what I did in my original prediction.  396.78 ppm + 2 ppm = 398.78 ppm (2013′s prediction).  398.78 ppm + 2 ppm = 400.78 ppm (2014′s prediction).  But if we use annual averages, we smooth out the large jumps in concentration values (like the 2013-2012 February difference).  There are other calculations that we could do to come up with a range of predictions, but I unfortunately don’t have the time to do them right now.  We will have to be content with waiting until early June to find out how fast concentrations are rising this year.

It is worth noting here that stations measured 400ppm CO2 concentration for the first time in the Arctic last year.  The Mauna Loa observations are usually closer to globally averaged values than other sites, such as in the Arctic.  That is why scientists and media reference the Mauna Loa observations most often.

 photo co2_widget_brundtland_600_graph_201302_zps1d2d45fe.gif

Figure 1 – Time series of CO2 concentrations measured at Scripp’s Mauna Loa Observatory in February: from 1959 through 2012.

This time series chart shows concentrations for the month of January in the Scripps dataset going back to 1959. As I wrote above, concentrations are persistently and inexorably moving upward.  How do concentration measurements change in calendar years?  The following two graphs demonstrate this.

 photo CO2_concentration_5y_trend_NOAA_201303_zpse1a5ad12.png

Figure 2 – Monthly CO2 concentration values from 2009 through 2013 (NOAA).  Note the yearly minimum observation is now in the past and we are two months removed from the yearly maximum value.  NOAA is likely to measure this year’s maximum value between 398ppm and 399ppm. photo CO2_concentration_50y_trend_NOAA_201303_zpscb598ad2.png

Figure 3 – 50 year time series of CO2 concentrations at Mauna Loa Observatory.  The red curve represents the seasonal cycle based on monthly average values.  The black curve represents the data with the seasonal cycle removed to show the long-term trend.  This graph shows the recent and ongoing increase in CO2 concentrations.  Remember that as a greenhouse gas, CO2 increases the radiative forcing toward the Earth, which eventually increases tropospheric temperatures.

In previous posts on this topic, I show and discuss historical and projected concentrations at this part of the post.  I will skip this for now because there is something about this data that I think provides a different context of the same conversation.  The increase in average annual concentrations in 2012 generated quite a bit of buzz in media outlets this week.  I dismissed the first couple of reports I saw because I’ve spent so much time during the past year writing about the concentrations.  But more media outlets wrote and discussed the same topic as the week went on.  So I think it is a valid story, especially after I saw a graphic that I thought should have been the focus the entire time:

 photo CO2_concentration_annual_growth_rate_NOAA_2012_zps4d9dfbcb.png

Figure 4 – CO2 concentration (top) and annual average growth rate (bottom). Source: Guardian

The top part of Figure 4 should look familiar – it’s the black line in Figure 3.  The bottom part is the annual change in CO2 concentrations.  If we fit a line to the data, the line would have a positive slope, which means annual changes are increasing with time.  So CO2 concentrations are increasing at an increasing rate – not a good trend with respect to minimizing future warming.  In the 1960s, concentrations increased at less than 1 ppm/year.  In the 2000s, concentrations increased at 2.07 ppm/year.

The greenhouse effect details how these concentrations will affect future temperatures.  The more GHGs in the atmosphere, all else equal, the more radiative forcing the GHGs cause.  More forcing means warmer temperatures as energy is re-radiated back toward the Earth’s surface.  Conditions higher in the atmosphere affects this relationship, which is what my volcano post addressed.  A number of medium-sized volcanoes injected SO2 into the stratosphere (which is above the troposphere – where we live and our weather occurs).  Those SO2 particles reflect incoming solar radiation.  So while we emitted more GHGs into the troposphere, less radiation entered the troposphere in the past 10 years than the previous 10 years.  With less incoming radiation, the GHGs re-emitted less energy toward the surface of the Earth.  This is likely part of the reason why the global temperature trend leveled off in the 2000s after its run-up in previous decades.

This situation is important for the following reason.  Once the SO2 falls out of the atmosphere, the additional incoming radiation will interact with higher GHG concentrations than was present in the late 1990s.  We will likely see a strong surface temperature response sometime in the future.

In my mind, the newsworthy detail is not that CO2 concentrations increased at the second fastest rate on record in 2012.  In climate, year-to-year differences matter less than long-term trends.  In my mind, the decadal concentration increase is what is noteworthy.  If concentrations rise by an average of >3 ppm/year in the 2010s or 2020s, a great deal of future warming and other climate change effects will occur.

It is my opinion that global temperature rise by 2100 will exceed 2C.  This target is primarily politically-driven.  Scientific research doesn’t exist that dictates 2C is “safe”.  Scientific research does exist that projects the likely temperature response to a range of CO2 concentration values.  If we do want to prevent >2C global temperature rise by 2100, we would have to immediately stop emitting CO2 and begin removing CO2 from the atmosphere.  We currently don’t have technologies to do either.

I have more to say about some details in the Guardian article from which I got Figure 4.  That will have to wait for another post.  The Science study the article mentions is worthy of discussion, as is the Guardian’s comment that concentrations continue to increase despite government action.  The article also links to a recent study of GHG reductions by 2020.  I will address these in an upcoming post.


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January 2013 CO2 Concentrations: 395.55ppm

Up and up the value goes.  The Scripps Institution of Oceanography measured an average of 395.55ppm CO2 concentration at their Mauna Loa, Hawai’i’s Observatory during January 2013.

395.55ppm is the highest value for January concentrations in recorded history. Last year’s 393.14ppm was the previous highest value ever recorded.  This January’s reading is 2.41ppm higher than last year’s.  This increase is significant.  Of course, more significant is the unending trend toward higher concentrations with time, no matter the month or specific year-over-year value, as seen in the graphs below.

The yearly maximum monthly value normally occurs during May. Last year was no different: the 396.78ppm concentration in May 2012 was the highest value reported last year and in recorded history (neglecting proxy data).  Note that January’s value is only 1.23ppm less than May 2012′s.  If we extrapolate last year’s maximum value out in time, it will only be 2 years until Scripps reports 400ppm average concentration for a singular month (likely May 2014; I expect May 2013′s value will be ~398ppm).  Note that I previously wrote that this wouldn’t occur until 2015 – this means CO2 concentrations are another climate variable that is increasing faster than experts predicted just a short couple of years ago.

It is worth noting here that stations measured 400ppm CO2 concentration for the first time in the Arctic last year.  The Mauna Loa observations are usually closer to globally averaged values than other sites, such as in the Arctic.  That is why scientists and media reference the Mauna Loa observations most often.

 photo co2_widget_brundtland_600_graph_201301_zps47426643.gif

Figure 1 – Time series of CO2 concentrations measured at Scripp’s Mauna Loa Observatory in January: from 1959 through 2012.

This time series chart shows concentrations for the month of January in the Scripps dataset going back to 1959. As I wrote above, concentrations are persistently and inexorably moving upward.  How do concentration measurements change in calendar years?  The following two graphs demonstrate this.

 photo CO2_concentration_5y_trend_NOAA_201302_zpsf91fb45e.png

Figure 2 – Monthly CO2 concentration values from 2009 through 2013 (NOAA).  Note the yearly minimum observation is now in the past and we are three months removed from the yearly maximum value.  NOAA is likely to measure this year’s maximum value at ~398ppm.

 photo CO2_concentration_50y_trend_NOAA_201302_zpsd23ef3f0.png

Figure 3 50 year time series of CO2 concentrations at Mauna Loa Observatory.  The red curve represents the seasonal cycle.  The black curve represents the data with the seasonal cycle removed to show the long-term trend.  This graph shows the recent and ongoing increase in CO2 concentrations.  Remember that as a greenhouse gas, CO2 increases the radiative forcing toward the Earth, which eventually increases lower tropospheric temperatures.

We could instead take a 10,000 year view of CO2 concentrations from ice cores and compare that to the recent Mauna Loa observations.  This allows us to determine how today’s concentrations compare to geologic conditions:

Photobucket

Figure 4 – Historical (10,000 year) CO2 concentrations from ice core proxies (blue and green curves) and direct observations made at Mauna Loa, Hawai’i (red curve) through the early 2000s.

Or we could take a really, really long view into the past:

Photobucket

Figure 5 – Historical record of CO2 concentrations from ice core proxy data, 2008 observed CO2 concentration value, and 2 potential future concentration values resulting from lower and higher emissions scenarios used in the IPCC’s AR4.

Note that this last graph includes values from the past 800,000 years, 2008 observed values (~8-10ppm less than this year’s average value will be) as well as the projected concentrations for 2100 derived from a lower emissions and higher emissions scenarios used by the IPCC’s Fourth Assessment Report from 2007.  Has CO2 varied naturally in this time period?  Of course it has.  But you can easily see that previous variations were between 180 and 280ppm and took thousands of years to move between the two.  In contrast, the concentration has, at no time during the past 800,000 years, risen to the level at which it currently exists; nor has the concentration changed so quickly (287ppm to 395ppm in less than two hundred years!).  That is important because of the additional radiative forcing that increased CO2 concentrations impart on our climate system.  You or I may not detect that warming on any particular day, but we are just starting to feel their long-term impacts.

Moreover, if our current emissions rate continues unabated, it looks like a tripling of average pre-industrial concentrations will be our reality by 2100 (278 *3 = 834).  Figure 5 clearly demonstrates how anomalous today’s CO2 concentration values are (much higher than the average, or even the maximum, recorded over the past 800,000 years).  It further shows how significant the projected emission pathways are.  I will point out that our actual emissions to date are greater than the higher emissions pathway shown above.  That means that if we continue to emit CO2 at an increasing rate, end-of-century concentration values would exceed the value shown in Figure 5 (~1100ppm instead of 800).  This reality will be partially addressed in the upcoming 5th Assessment Report (AR5), currently scheduled for public release in 2013-14.

Given our historical emissions to date and the likelihood that they will continue to grow at an increasing rate for at least the next 25 years, we will pass a number of “safe” thresholds – for all intents and purposes permanently as far as concerns our species. It is time to start seriously investigating and discussing what kind of world will exist after CO2 concentrations peak at 850 or 1200ppm. No knowledgeable body, including the IPCC, has done this to date. To remain relevant, I think institutions who want a credible seat at the climate science-policy table will have to do so moving forward.  The work leading up to AR5 will begin to fill in some of this knowledge gap.  I expect most of that work has recently started and will be available to the public around the same time as the AR5 release.  This could potentially cause some confusion in the public since the AR5 will tell one storyline while more recent research might tell a different storyline.

The fourth and fifth graphs imply that efforts to pin any future concentration goal to a number like 350ppm or even 450ppm will be incredibly difficult – 350ppm more so than 450ppm, obviously. Beyond an education tool, I don’t see the utility in using 350ppm – we simply will not achieve it, or anything close to it, given our history and likelihood that economic growth goals will trump any effort to address CO2 concentrations in the near future (as President Obama himself stated in 2012).  That is not to say that we should abandon hope or efforts to do something.  On the contrary, this series informs those who are most interested in action.  With a solid basis in the science, we become equipped to discuss policy options.  I join those who encourage efforts to tie emissions reductions to economic growth through scientific and technological research and innovation.  This path is the only credible one moving forward.


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Climate Sensitivity and 21st Century Warming

I want to write about shoddy opining today.  I will also write about tribalism and cherry-picking; all are disappointing aspects in today’s climate discussion.  In climate circles, a big kerfuffle erupted in the past week that revolves around minutiae and made worse by disinformation.  The Research Group of Norway released a press release that somebody’s research showed a climate sensitivity of ~1.9°C (1.2-2.9°C was the range around this midpoint value) due to CO2-doubling, which is lower than other published values.

Important Point #1: The work remains un-peer reviewed.  It is part of unpublished PhD work and therefore subject to change.

Moving from that context, what happened next?  The Inter-tubes were ablaze with skeptics cheering the results.  Additionally, groups like Investor’s Business Daily jumped on the “global warming is hooey” bandwagon.  Writers like Andy Revkin provided thoughtful analysis.

Important Point #2: Skeptics view some model results as truthful – those that agree with their worldview.

IBD can, of course, opine all it wants about this topic.  What obligation to their readers do they have to disclose their biases, however?  All the other science results are wrong, except this one with which they agree.  What makes the new results so correct when every other result is so absolutely wrong?  Nothing, as I show below.

Important Point #3: These preliminary results still show a sensitivity to greenhouse gas emissions, not to the sun or any other factor.

For additional context, you should ask how these results differ from other results.  What are IBD and other skeptics crowing about?

 photo Climate_Sensitivity_500_zps9f1bcb3a.jpg

Figure 1Distributions and ranges for climate sensitivity from different lines of evidence. The circle indicates the most likely value. The thin colored bars indicate very likely value (more than 90% probability). The thicker colored bars indicate likely values (more than 66% probability). Dashed lines indicate no robust constraint on an upper bound. The IPCC likely range (2 to 4.5°C) is indicated by the vertical light blue bar. [h/t Skeptical Science]

They’re crowing about a median value of 1.9°C in a range of 1.2-2.9°C.  If you look at Figure 1, neither the median nor the range is drastically different from other estimates.  The range is a little smaller in magnitude than what the IPCC reported in 2007.  Is it surprising that if scientists add 10 more years of observation data to climate models, a sensitivity measurement might shift?  The IPCC AR4 dealt with observations through 2000.  This latest preliminary report used observations through 2010.  What happened in the past 10 years that might shift sensitivity results?  Oh, a number of La Niñas, which are global cooling events.  Without La Niñas, the 2000s would have been warmer, which would have affected the sensitivity measurement differently.  No  mention of this breaks into the opinion piece.

Important Point #4: Climate sensitivity and long-term warming are not the same thing.

The only case in which they are the same thing is if we limit our total emissions so that CO2 concentrations are equal to CO2-doubling.  That is, if CO2 concentrations peak at 540ppm sometime in the future, the globe will likely warm no more than 1.9°C.  Note that analysis’s importance.  It brings us to:

Important Point #5: On our current and projected emissions pathway, we will more than double pre-industrial CO2 concentrations.

 photo CO2_Emissions_IPCC_Obs_2011_zpsa00aa5e8.jpg

Figure 2.  Historical emissions (IEA data – black) compared to IPCC AR4 SRES scenario projections (colored lines).

As I’ve discussed before, our historical emissions continue to track at the top of the range considered by the IPCC in the AR4 (between A2 and A1FI).  Scientists are working on the AR5 as we speak, but the framework for the upcoming report changed.  Instead of emissions, planners built Representative Concentration Pathways (RCPs) for the AR5.  A graph that shows these pathways is below.  This graph uses emissions to bridge between the AR4 and AR5.

 photo CO2EmissionsScenarios-hist-and-RCP-2012.png

Figure 3. Representative Concentration Pathways used in the upcoming AR5 through the year 2100, displayed using yearly emissions estimates.

The top line (red; RCP8.5) corresponds to the A1FI/A2 SRES scenarios.  As Figure 3 shows, our historical emissions most closely match the RCP8.5 pathway.  The concentration for this pathway through 2100 is 1370ppm CO2-eq, which results in an anomalous +8.5W/m^2 forcing.  This forcing is likely to result in 4 to 6.1°C warming by 2100.  A couple of critical points: in this scenario, emissions don’t peak in the 21st century; therefore this scenario projects additional warming in the 2100s.  I want to make absolutely clear this point: our business-as-usual concentration pathway blows past CO2-doubling this century, which means the doubling sensitivity is a moot point.  We should investigate CO2-quadrupliung.  Why?  The peak emissions and concentration, which dictates the peak anomalous forcing, which controls the peak warming we face.

The IBD article contains plenty of skeptic-speak: “Predictions of doom have turned out to be nothing more than madness”, “there are too many unknowns, too many variables”, and “nothing ever proposed would have any impact anyway”.

They do have a point with their first quoted statement.  I avoid catastrophic language because doom has not befallen the vast majority of people on this planet.  Conditions are changing, to be sure, but not drastically.  There are too many unknowns.  Most of the unknowns scientists worked on the last 10 years ended up with the opposite result that IBD assumes: scientists underestimated feedbacks and results.  Events unfolded much more quickly than previously projected.  That will continue in the near future due mainly to our lack of knowledge.  The third point is a classic: we cannot act because others will not act in concert with us.  This flies in the face of a capitalist society’s foundation.  Does IBD really believe that US innovation will not increase our competitiveness or reduce inefficiencies?  Indeed, Tim Worstall’s Forbes piece posited a significant conclusion: climate change becomes cheaper to solve if the sensitivity is lower than previously estimated.  IBD should be cheering for such a result.

Finally, when was the last time you saw the IBD latch onto one financial model and completely discard others?  Where was IBD in 2007 when the financial crisis was about to start and a handful of skeptics warned that the mortgage boom was based on flawed models?  Were they writing opinion pieces like this one?  I don’t think so.  Climate change requires serious policy consideration.  This opinion piece does nothing to materially advance that goal.


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December 2012 CO2 Concentrations: 394.39ppm

The Scripps Institution of Oceanography measured an average of 394.39ppm CO2 concentration at their Mauna Loa, Hawai’i’s Observatory during December 2012.

394.39ppm is the highest value for December concentrations in recorded history. Last year’s 391.79ppm was the previous highest value ever recorded.  This December’s reading is 2.60ppm higher than last year’s.  This increase is significant.  Of course, more significant is the unending trend toward higher concentrations with time, no matter the month or specific year-over-year value, as seen in the graphs below.

The yearly maximum monthly value normally occurs during May. Last year was no different: the 396.78ppm concentration in May 2012 was the highest value reported this year and in recorded history (neglecting proxy data).  Note that December 2012′s value is only 2.39ppm less than May 2012′s.  If we extrapolate last year’s maximum value out in time, it will only be 2 years until Scripps reports 400ppm average concentration for a singular month (likely May 2014; I expect May 2013′s value will be ~398ppm).  Note that I previously wrote that this wouldn’t occur until 2015 – another climate variable that is increasing faster than energy or climate experts predicted.

It is worth noting here that stations measured 400ppm CO2 concentration for the first time in the Arctic last year.  The Mauna Loa observations represent more well-mixed (global) conditions while sites in the Arctic and elsewhere more accurately measure local and regional concentrations.  That is why scientists and media reference the Mauna Loa observations most often.

Earlier last year, I predicted that 2012 would not see an average monthly CO2 concentration below 390ppm.  I was correct: September and October 2012 concentration values were the lowest recorded last year (391ppm).  It wasn’t the hardest prediction to make: the trend was going up at a steady rate and based on humanity’s continued reliance on fossil fuels, we weren’t going to break that trend.  The next prediction to verify is the first month at Mauna Loa during which Scripps records an 400ppm average.  After that, the first year during which the minimum concentration is at least 400ppm, which I think will occur within the next 5 years.

Photobucket

Figure 1 – Time series of CO2 concentrations measured at Scripp’s Mauna Loa Observatory in December: from 1958 through 2012.

This time series chart shows concentrations for the month of December in the Scripps dataset going back to 1958. As I wrote above, concentrations are persistently and inexorably moving upward.  How do concentration measurements change in calendar years?  The following two graphs demonstrate this.

Photobucket

Figure 2 – Monthly CO2 concentration values from 2008 through 2013 (NOAA).  Note the yearly minimum observations are now in the past and we are five months removed from the yearly maximum value.

Photobucket

Figure 3 50 year time series of CO2 concentrations at Mauna Loa Observatory.  The red curve represents the seasonal cycle.  The black curve represents the data with the seasonal cycle removed to show the long-term trend.  This graph shows the ongoing increase in CO2 concentrations.  Remember that as a greenhouse gas, CO2 increases the radiative forcing toward the Earth, which eventually increases lower tropospheric temperatures.

We could instead take a 10,000 year view of CO2 concentrations from ice cores and compare that to the recent Mauna Loa observations.  This allows us to determine how today’s concentrations compare to geologic conditions:

Photobucket

Figure 4 – Historical (10,000 year) CO2 concentrations from ice core proxies (blue and green curves) and direct observations made at Mauna Loa, Hawai’i (red curve).

Or we could take a really, really long view into the past:

Photobucket

Figure 5 – Historical record of CO2 concentrations from ice core proxy data, 2008 observed CO2 concentration value, and 2 potential future concentration values resulting from lower and higher emissions scenarios used in the IPCC’s AR4.

Note that this last graph includes values from the past 800,000 years, 2008 observed values (~8-10ppm less than this year’s average value will be) as well as the projected concentrations for 2100 derived from a lower emissions and higher emissions scenarios used by the IPCC’s Fourth Asssessment Report from 2007.  Has CO2 varied naturally in this time period?  Of course it has.  But you can easily see that previous variations were between 180 and 280ppm.  In contrast, the concentration has, at no time during the past 800,000 years, risen to the level at which it currently exists.  That is important because of the additional radiative forcing that increased CO2 concentrations impart on our climate system.  You or I may not detect that warming on any particular day, but we are just starting to feel their long-term impacts.

Moreover, if our current emissions rate continues unabated, it looks like a tripling of average pre-industrial concentrations will be our reality by 2100 (278 *3 = 834).  Figure 5 clearly demonstrates how anomalous today’s CO2 concentration values are (much higher than the average, or even the maximum, recorded over the past 800,000 years).  It further shows how significant projected emission pathways are.  I will point out that our actual emissions to date are greater than the higher emissions pathway shown above.  That means that if we continue to emit CO2 at an increasing rate, end-of-century concentration values would exceed the value shown in Figure 5.  This reality will be partially addressed in the upcoming 5th Assessment Report (AR5), currently scheduled for public release in 2013-14.

Given our historical emissions to date and the likelihood that they will continue to grow at an increasing rate for at least the next 25 years, we will pass a number of “safe” thresholds – for all intents and purposes permanently as far as concerns our species. It is time to start seriously investigating and discussing what kind of world will exist after CO2 concentrations peak at 850 or 1200ppm. No knowledgeable body, including the IPCC, has done this to date. To remain relevant, I think institutions who want a credible seat at the climate science-policy table will have to do so moving forward.  The work leading up to AR5 will begin to fill in some of this knowledge gap.  I expect most of that work has recently started and will be available to the public around the same time as the AR5 release.  This could potentially cause some confusion in the public since the AR5 will tell one storyline while more recent research might tell a different storyline.

The fourth and fifth graphs imply that efforts to pin any future concentration goal to a number like 350ppm or even 450ppm will be incredibly difficult – 350ppm more so than 450ppm, obviously. Beyond an education tool, I don’t see the utility in using 350ppm – we simply will not achieve it, or anything close to it, given our history and likelihood that economic growth goals will trump any effort to address CO2 concentrations in the near future (as President Obama himself stated in 2012).  That is not to say that we should abandon hope or efforts to do something.  On the contrary, this series informs those who are most interested in doing something.  With a solid basis in the science, we become well equipped to discuss policy options.  I join those who encourage efforts to tie emissions reductions to economic growth through scientific and technological research and innovation.  This path is the only credible one moving forward.


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November 2012 CO2 Concentrations: 392.92ppm

The Scripps Institution of Oceanography measured an average of 392.92ppm CO2 concentration at their Mauna Loa, Hawai’i’s Observatory during November 2012.

392.92ppm is the highest value for November concentrations in recorded history. Last year’s 390.31ppm was the previous highest value ever recorded.  This November’s reading is 2.61ppm higher than last year’s.  This increase is significant.  Of course, more significant is the unending trend toward higher concentrations with time, no matter the month or specific year-over-year value, as seen in the graphs below.

The yearly maximum monthly value normally occurs during May. This year was no different: the 396.78ppm concentration in May 2012 was the highest value reported this year and in recorded history (neglecting proxy data).  If we extrapolate this year’s maximum value out in time, it will only be 2 years until Scripps reports 400ppm average concentration for a singular month (likely May 2014).  Note that I previously wrote that this wouldn’t occur until 2015 – another climate variable that is increasing faster than energy or climate experts predicted.

I’ve seen comments in the skeptic blogosphere that CO2 measured at Mauna Loa should be higher than anywhere else because of its elevation and specific location.  This is an effort to challenge the credibility of the dataset.  It is important to understand that this statement exists somewhere between correct to purposefully confusing to outright deceitful.  CO2 is a well-mixed constituent of the atmosphere.  That means that emissions of new CO2 are quickly and pretty evenly distributed in space.  While point locations might vary between each other (differences between polar and tropical CO2 concentrations at the same point in time vary the most, for example), the observations at Mauna Loa are very representative of those found across the set of observation stations on the globe.  In addition, as the graphs below will help demonstrate, the historical record is very clear – concentrations have done only one thing in the past 50+ years at any station you want to discuss: increased.  There has been no plateauing or decrease in that time period.

That being said, it is worth noting here that stations measured 400ppm CO2 concentration for the first time in the Arctic earlier this year.  The Mauna Loa observations represent more well-mixed (global) conditions while sites in the Arctic and elsewhere more accurately measure local and regional concentrations.  That is why scientists and media reference the Mauna Loa observations most often.

Earlier in the year, I predicted that 2012 would not see an average monthly CO2 concentration below 390ppm.  It wasn’t the hardest prediction to make: the trend was going up at a steady rate and based on humanity’s continued reliance on fossil fuels, we weren’t going to break that trend this year.  The next prediction to verify is the first month at Mauna Loa during which Scripps records an 400ppm average.  After that, the first year during which the minimum concentration is at least 400ppm, which I think will occur within the next 5 years.

Photobucket

Figure 1 – Time series of CO2 concentrations measured at Scripp’s Mauna Loa Observatory in November: from 1958 through 2012.

This time series chart shows concentrations for the month of November in the Scripps dataset going back to 1958. As I wrote above, concentrations are persistently and inexorably moving upward. Alternatively, we could take a 10,000 year view of CO2 concentrations from ice cores and compare that to the recent Mauna Loa observations:

Photobucket

Figure 2 – Historical (10,000 year) CO2 concentrations from ice core proxies (blue and green curves) and direct observations made at Mauna Loa, Hawai’i (red curve).

Or we could take a really, really long view into the past:

Photobucket

Figure 3 – Historical record of CO2 concentrations from ice core proxy data, 2008 observed CO2 concentration value, and 2 potential future concentration values resulting from lower and higher emissions scenarios used in the IPCC’s AR4.

Note that this graph includes values from the past 800,000 years, 2008 observed values (~6-8ppm less than this year’s average value will be) as well as the projected concentrations for 2100 derived from a lower emissions and higher emissions scenarios used by the IPCC’s Fourth Asssessment Report from 2007.  Has CO2 varied naturally in this time period?  Of course it has.  But you can easily see that previous variations were between 180 and 280ppm.  In contrast, the concentration has, at no time during the past 800,000 years, risen to the level at which it currently exists.  That is important because of the additional radiative forcing that increased CO2 concentrations impart on our climate system.  You or I may not detect that warming on any particular day, but we are just starting to feel their long-term impacts.

Moreover, if our current emissions rate continues unabated, it looks like a tripling of average pre-industrial concentrations will be our reality by 2100 (278 *3 = 834).  This graph clearly demonstrates how anomalous today’s CO2 concentration values are (much higher than the average recorded over the past 800,000 years).  It further shows how significant projected emission pathways are.  I will point out that our actual emissions to date are greater than the higher emissions pathway shown above.  This reality will be partially addressed in the upcoming 5th Assessment Report (AR5), currently scheduled for public release in 2013-14.

Given our historical emissions to date and the likelihood that they will continue to grow at an increasing rate for at least the next 25 years, we will pass a number of “safe” thresholds – for all intents and purposes permanently as far as concerns our species. It is time to start seriously investigating and discussing what kind of world will exist after CO2 concentrations peak at 850 or 1100ppm. No knowledgeable body, including the IPCC, has done this to date. To remain relevant, I think institutions who want a credible seat at the climate science-policy table will have to do so moving forward.  The AR5 might possibly fill in some of this knowledge gap.  I expect most of that work has recently started and will be available to the public around the same time as the AR5 release, which is likely to cause some confusion in the public.

As the second and third graphs imply, efforts to pin any future concentration goal to a number like 350ppm or even 450ppm will be incredibly difficult – 350ppm more so than 450ppm, obviously. Beyond an education tool, I don’t see the utility in using 350ppm – we simply will not achieve it, or anything close to it, given our history and likelihood that economic growth goals will trump any effort to address CO2 concentrations in the near future (as President Obama himself stated recently).  That is not to say that we should abandon hope or efforts to do something.  On the contrary, this series informs those who are most interested in doing something.  With a solid basis in the science, we become well equipped to discuss policy options.  I join those who encourage efforts to tie emissions reductions to economic growth through scientific and technological research and innovation.  This path is the only credible one moving forward.

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