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Bridging climate science, citizens, and policy

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GHG Emissions: 2C Pathways Are A Fantasy

A new commentary piece in Nature Climate Change continues to make significant errors and propagates a mistaken core assumption too many in the climate community make: that with enough [insert: political will or technological breakthroughs], 2C warming is still an achievable goal.

I have disagreed with this assumption and therefore its conclusion for six years – ever since establishment Democrats decided to waste valuable political capital on a right-wing insurance bill with a vague promise that climate legislation would come someday.  That decision essentially assured that, absent a global economic collapse or catastrophic geologic events, our species would easily push the planet past 2C warming.

The following graphic shows global historical emissions in solid black.  The green curve represents the fantasy projection of an emissions pathway that leads to <2C global warming.  As you can see, emissions have to start declining this year in the assumed scenario.  The yellow curve represents what is likely to happen if climate action is delayed for 8 years and this year’s emissions remain constant during those 8 years.  It gets increasingly difficult to achieve the same long-term warming cap because of that 8 year delay.

The red curve builds on the yellow curve projection by keeping the next 8 year’s emissions constant but reducing federal money to research decarbonization technology.  This is the linchpin to any emissions pathway that could potentially put us on a pathway to a less warm climate.  Decarbonization technology has to not only be fully researched but fully deployed on a planetary scale for the 2C pathway to happen.  It’s hard to see on this graph, but global emissions have to go net negative for us to achieve <2C warming.  While the yellow curve has a harder time achieving that than the green curve, the red curve doesn’t get there one century from now.  But the red curve isn’t the most likely pathway – it wasn’t in 2010 and it isn’t today.

The most likely pathway is the solid black curve out to 2125.  It assumes the same things as the red curve and adds an important component of reality: emissions are likely to increase in the near-term due to continued increased fossil fuel use.  Natural gas and coal plants continue to be built – any assumption otherwise might be interesting academically but has no place in the real world.  By assuming otherwise, scientists make themselves a target of future policy makers because the latter won’t pay attention to the nuanced arguments the scientists will make once it’s clear we’re hurtling past 2C.  Once we burn increasing amounts of fossil fuels during the next 8 years (as we did the 8 years before that and so on), it is harder still to cut emissions fast enough to try to keep global warming <2C.  The reasons should be obvious: the emitted GHGs will radiatively warm the planet so long as they’re in the atmosphere and it will take even more technological breakthroughs to achieve the level of carbon removal necessary to keep warming below some level.


The authors recognize this challenge:

[…]to remain within a carbon budget for 2 °C in the baseline scenario considered, peak reduction rates of CO2 emissions around 2.4% per year are needed starting mitigation now. A global delay of mitigation action of eight years increases that to 4.2% per year (black dashed in Fig. 1a) — extremely challenging both economically and technically. The only alternative would be an overshoot in temperature and negative emissions thereafter. Research in negative emissions should therefore be a priority, but near term policy should work under the assumption that such technology would not be available at large scale and low cost soon.

I disagree with the author’s conclusion:

Society is at a crossroad, and the decisions made in the US and elsewhere over the next 4–8 years may well determine if it is possible to limit climate change to levels agreed in Paris.

We passed the crossroad already.  It really doesn’t matter when, the fact is we passed it.  I think it is a waste of time to examine low-end emission scenarios for policy purposes.  They serve some scientific use.  Policy makers need relevant scientific advice and 2C scenarios don’t do that.  They perpetuate a myth and therefore pose a real danger to society.  The so-called reality-based community needs to critically self-examine what they’re doing and why they’re doing it.  We’re headed for >3C warming and we need to come to terms with what that means.

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What will 2040 US GHG emissions be

if this graph is anywhere close to accurate?

 photo Electricgeneratingcapacityadditions2000-2040-EIA_zpsa9ed57ae.png

That projection of electric generating capacity additions does not get us to stated emissions goals (e.g., 80% or 90% of 2005 levels by 2050.)  We can easily observe that out-year EIA projections probably are not very accurate and that’s a fair point.  I doubt, for instance, that this graph takes the EPA’s recent proposed rule into account.  The next 5-10 years is probably close to what will happen, however – close enough that any difference will not significantly impact say 2030 or 2040 emissions.

Note the vast difference between natural gas/oil additions for any single year between 2000-2005 and total renewables during any other year.  The only year that comes close to the same size for renewables will be 2015, but that still only amounts to 1/3 to 1/2 the natural gas additions ten years ago.  In order to achieve stated emissions goals, renewable additions will have to double every year between now and 2040.  That’s because new additions have to replace the oldest coal plants first, followed by oldest natural gas plants, and also meet increasing future demand, and generate enough energy during peak production periods to exceed peak consumption periods (not the same times of day).

Additionally, if we want to keep global mean annual temperature increases <2C, the projected natural gas additions have to tail off to zero (not stay constant) because they still emit GHGs.  And if all of that weren’t challenging enough, we must remove carbon from the atmosphere that is due to historical combustion and leakage.  But the basic story of this graph remains: this projection will not enable us to achieve stated emission reduction goals.  This graph is therefore useful in helping us understand what policies are working and what needs to be done in order to approach our emission goal.  For instance, renewables appear to enter a period of no growth in the 2020s.  That is probably unrealistic, but what policies should we consider to boost their deployment above 2005-2010 levels during the 2020s and on into the 2030s and beyond?  How about finance policies for starters?  How about long-term federal and state guarantees?  If we enact the EPA’s proposed power plant rule in most any way close to how it is currently structured, the 2020s and 2030s will likely look very different from this.  That rule could be a good start toward meeting future goals (just not 90% reduction by 2050 or <2C warming; more like 30% reduction by 2050).


REMI’s Carbon Tax Report

I came across former NASA climate scientist James Hansen’s email last week supporting a carbon tax.  At the outset, I fully support this policy because it is the most economically effective way to achieve CO2 emission reductions.  An important point is this: it matters a lot how we apply the tax and what happens to the money raised because of it.  Many policy analysts think that the only way a carbon tax will ever pass is for the government to distribute the revenue via dividends to all households.  This obviously has appealing aspects, not least of which is Americans love free stuff.  That is, we love to reap the benefits of policies so long as they cost us nothing.  That attitude is obviously unsustainable – you have simply to look at the state of American infrastructure today to see the effects.

All that said, the specific carbon tax plan Hansen supported came from a Regional Economic Models, Inc. report, which the Citizens Climate Lobby commissioned.  The report found what CCL wanted it to find: deep emission cuts can result from a carbon tax.  There isn’t anything surprising with this – many other studies found the exact same result.  What matters is how we the emission cuts are achieved.  I think this study is another academic dead-end because I see little evidence how the proposed tax actually achieves the cuts.  It looks like REMI does what the IPCC does – they assume large-scale low-carbon energy technologies.  The steps of developing and deploying those technologies are not clearly demonstrated.  Does a carbon tax simply equate to low-carbon technology deployment?  I don’t think so.

First, here is an updated graphic showing REMI’s carbon emission cuts compared to other sources:

 photo EPA2014vsEIA2012vsKyotovsREMI2014_zps961bb7c7.png

The blue line with diamonds shows historical CO2 emissions.  The dark red line with squares shows EIA’s 2013 projected CO2 emissions through 2030.  EIA historically showed emissions higher than those observed.  This newest projection is much more realistic.  Next, the green triangles show the intended effect of EPA’s 2014 power plant rule.  I compare these projections against Kyoto `Low` and `High` emission cut scenarios.  An earlier post showed and discussed these comparisons.  I added the modeled result from REMI 2014 as orange dots.

Let me start by noting I have written for years now that we will not achieve even the Kyoto `Low` scenario, which called for a 20% reduction of 1990 baseline emissions.  The report did not clearly specify what baseline year they considered, so I gave them the benefit of the doubt in this analysis and chose 2015 as the baseline year.  That makes their cuts easier to achieve since 2015 emissions were 20% higher than 1990 levels.  Thus, their “33% decrease from baseline” by 2025 results in emissions between Kyoto’s `Low` and `High` scenarios.

REMI starts with a $10 carbon tax in 2015 and increases that tax by $10/year.  In 10 years, carbon costs $100/ton.  That is an incredibly aggressive taxing scheme.  This increase would have significant economic effects.  The report describes massive economic benefits.  I will note that I am not an economist and don’t have the expertise to judge the economic model they used.  I will go on to note that as a climate scientist, all models have fundamental assumptions which affect the results they generate.  The assumptions they made likely have some effect on their results.

Why won’t we achieve these cuts?  As I stated above, technologies are critical to projecting emission cuts.  What does the REMI report show for technology?

 photo REMI2014ElectricalPowerGeneration-2scenarios_zpse41c17d9.png

The left graph shows US electrical power generation without any policy intervention (baseline case).  The right graph shows generation resulting from the $10/year carbon tax policy.  Here is their models’ results: old unscrubbed coal plants go offline in 2022 while old scrubbed coal plants go offline in 2025.  Think about this: there are about 600 coal plants in the US generating the largest single share of electricity of any power source.  The carbon tax model results assumes that other sources will replace ~30% of US electricity in 10 years.  How will that be achieved?  This is the critical missing piece of their report.

Look again at the right graph.  Carbon captured natural gas replaces natural gas generation by 2040.  Is carbon capture technology ready for national-level deployment?  No, it isn’t.  How does the report handle this?  That is, who pays for the research and development first, followed by scaled deployment?  The report is silent on this issue.  Simply put, we don’t know when carbon capture technology will be ready for scaled deployment.  Given historical performance of other technologies, it is safe to assume this development would take a couple of decades once the technology is actually ready.

Nuclear power generation also grows a little bit, as does geothermal and biopower.  This latter technology is interesting to note since it represents the majority of the percentage increase of US renewable power generation in the past 15 years (based on EIA data) – something not captured by their model.

The increase in wind generation is astounding.  It grows from a few hundred Terawatt hours to over 1500 TWh in 20 years time.  This source is the obvious beneficiary to a carbon tax.  But I eschew hard to understand units.  What does it mean to replace the majority of coal plants with wind plants?  Let’s step back from academic exercises that replace power generation wholesale and get into practical considerations.  It means deploying more than 34,000 2.5MW wind turbines operating at 30% efficiency per year every year.  (There are other metrics by which to convey the scale, but they deal with numbers few people intuitively understand.)  According to the AWEA, there were 46,100 utility-scale wind turbines installed in the US at the end of 2012.  How many years have utilities installed wind turbines?  Think of the resources required to install almost as many wind turbines in just one year as already exist in the US.  Just to point out one problem with this installation plan: where do the required rare earth metals come from?  Another: are wind turbine supply chains up to the task of manufacturing 34,000 wind turbines per year?  Another: are wind turbine manufacturing plants equipped to handle this level of work?  Another: are there enough trained workers to supply, make, transport, install, and maintain this many wind turbines?  Another: how is wind energy stored and transmitted from source to use regions (thousands of miles in many cases).

Practical questions abound.  This report is valuable as an academic exercise, but  I don’t see how wind replaces coal in 20 years time.  I want it to, but putting in a revenue-neutral carbon tax probably won’t get it done.  I don’t see carbon capture and sequestration ready for scale deployment in 10 years time.  I would love to be surprised by such a development but does a revenue-neutral carbon tax generate enough demand for low-risk seeking private industry to perform the requisite R&D?  At best, I’m unconvinced it will.

After doing a little checking, a check reminded me that British Columbia implemented a carbon tax in 2008; currently it is $40 (Canadian).  Given that, you might think it serves as a good example of what the US could do with a similar tax.  If you dig a little deeper, you find British Columbia gets 86% of its electricity from hydropower and only 6% from natural gas, making it a poor test-bed to evaluate how a carbon tax effects electricity generation in a large, modern economy.


EPA’s Proposed CO2 Emissions Rule in Context

 photo EPA2014vsEIA2012vsKyoto_zps8d150e25.png

If you follow climate and energy news, you probably have or will encounter media regarding today’s proposed CO2 emissions rule by the EPA.  Unfortunately, that media will probably not be clear about what the rule means in understandable terms.  I’m writing this in an attempt to make the proposed rule more clear.

The graph above shows US CO2 emissions from energy consumption.  This includes emissions from coal, oil, and natural gas.  I have differentiated historical emissions in blue from 2013 EIA projections made in red, what today’s EPA proposal would mean for future emission levels, and low and high reductions prescribed by the Kyoto Protocol, which the US never ratified.

In 2011, historical US energy-related emissions totaled 5,481 million metric tons of CO2.  For the most part, you can ignore the units and just concentrate on emission’s magnitude: 5,481.  If the EPA’s proposed rule goes into effect and achieves what it sets out to achieve, 2020 emissions could be 4,498 MMT and 2030 emissions could be 4,198 MMT (see the two green triangles).  Those 2030 emissions would be lower than any time since 1970 – a real achievement.  It should be apparent by the other comparisons that this potential achievement isn’t earth shaking however.

Before I get further into that, compare the EPA-related emissions with the EIA’s projections out to 2030.  These projections were made last year and are based on business as usual – i.e., no federal climate policy or EPA rule.  Because energy utilities closed many of their dirtiest fossil fuel plants following the Great Recession due to their higher operating costs and the partial transfer from coal to natural gas, the EIA now projects emissions just above 2011’s and below the all-time peak.  I read criticism of EIA projections this weekend (can’t find the piece now) that I think was too harsh.  The EIA historically projected emissions in excess of reality.  I don’t think their over-predictions are bad news or preclude their use in decision-making.  If you know the predictions have a persistent bias, you can account for it.

So there is a measurable difference between EIA emission projections and what could happen if the EPA rule is enacted and effective.  With regard to that latter characterization, how effective might the rule be?

If you compare the EPA emission reductions to the Kyoto reductions, it is obvious that the reductions are less than the minimum requirement to avoid significant future climate change.  But first, it is important to realize an important difference between Kyoto and the EPA rule: the Kyoto pathways are based off 1990 emissions and the EPA is based off 2005 emissions.  What happened between 1990 and 2005 in the real world?  Emissions rose by 19% from 5,039 MMT to 5,997 MMT.  The takeaway: emission reductions using 2005 as a baseline will result in higher final emissions than using a 1990 baseline.

If the US ratified and implemented Kyoto on the `Low` pathway (which didn’t happen), 2020 emissions would be 4,031 MMT (467 MMT less than EPA; 1445 MMT less than EIA) and 2050 emissions would be 2,520 MMT (no comparison with EPA so far).  If the US implemented the `High` pathway, 2020 emissions would be 3,527 MMT (971 MMT less than EPA!; 1,949 MMT less than EIA!) and 2050 emissions would be drastically slashed to 1,008 MMT!

Since we didn’t implement the Kyoto Protocol, we will not even attain 2020 `Kyoto Low` emissions in 2030.  Look at the graph again.  Connect the last blue diamond to the first green triangle.  Even though they’re the closest together, you can immediately see we have a lot of work to do to achieve even the EPA’s reduced emissions target.  Here is some additional context: to keep 2100 global mean temperatures <2C, we have to achieve the lowest emissions pathway modeled by the IPCC for the Fifth Assessment Report (see blue line below):

 photo CO2_Emissions_AR5_Obs_Nature_article_zps1e766d71.jpg

Note the comment at the bottom of the graph: global CO2 emissions have to turn negative by 2070, following decades of declines.  How will global emissions decline and turn negative if the US emits >3,000 MMT annually in 2050?  The short answer is easy: they won’t.  I want to combine my messages so far in this post: we have an enormous amount of work to reduce emissions to the EPA level.  That level is well below Kyoto’s Low level, which would have required a lot of work in today’s historical terms.  That work now lies in front of us if we really want to avoid >2C warming and other effects.  I maintain that we will not reduce emissions commensurate with <2C warming.  I think we will emit enough CO2 that our future will be along the RCP6.0 to RCP8.5 pathways seen above, or 3-5C warming and related effects.

Another important detail: the EPA’s proposed rule has a one-year comment period which will result in a final rule.  States then have another year to implement individual plans to achieve their reductions (a good idea).  The downside: the rule won’t go into effect until 2016 – only four years before the first goal.  What happens if the first goal isn’t achieved?  Will future EPA administrators reset the 2030 goal so it is more achievable (i.e., higher emissions)?  Will lawsuits prevent rule implementation for years?  There are many potential setbacks for implementing this rule.  And it doesn’t achieve <2C warming, not even close.

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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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Climate & Energy Articles – Aug. 17, 2013

Since I can’t devote as much time to everything I read, here is a quick roundup of things I thought were interesting recently:

A Nature article (subs. req’d) describes some of the problems with a trending climate effort: decadal predictions.  In the past, agencies just made climate projections for a couple of centuries into the future.  In addition to that, interest in projections over the next 10 or 20 years grew.  Unfortunately, climate models aren’t well designed for these short time frames.  Thus, they miss high-frequency climate events made just after agencies issue them.  Of particular concern are the high impact events, as we tend to focus on them.  I would remind critics that point out these “misses” that very few financial models indicated the biggest economic disruption of our lifetime: the Great Recession, yet we continue to ascribe great status to the same financial titans that universally missed that high impact event.  That means, of course, that critics remain within their tribal identities and look for any evidence to support their position, even as they ignore similar evidence for analogous cases.

A group made an interesting counter argument regarding the cause behind the US’s recent drop in CO2 emissions.  Instead of the switch from carbon-intensive coal to slightly less intensive natural gas, as many analysts described, this group claims the drop occurred due to widespread, massive efficiency gains.  I characterize this as interesting because the group is countering the International Energy Agency, among others.  While not prescient, the IEA is the leading authority in these types of analyses.  We shouldn’t take their analyses without a grain of salt, of course, as their methodologies are likely imperfect.  Instead, this new argument should encourage further research and analysis.  Was the coal-to-gas switch primarily responsible or was efficiency?  Additional years’ data will help to clarify the respective roles.  In the long-term, efficiency can play as big or a bigger role than the coal-to-gas switch that occurred to date.  That’s where innovation funded from a carbon price comes into play.

Grist ran an informative series recently that included a short video of how much energy the US uses – the primary generators and consumers by type and sector.  The upshot is this: the US uses 100 quads (an energy measurement), which makes further discussion quite simple.  The US generates 81-83 quads (81-83%) via fossil fuels (oil, coal, and natural gas).  That leaves only 17-19% of US generation by non-fossil sources.  Most non-fossil energy generation is nuclear, which means renewables account for the smallest share of energy generation.  Most of that is hydropower from dams that we built in the first half of the 20th century.  This data will form the basis of my next post, which will examine the implications of this energy breakdown for climate policy.  What will it take to replace 83 quads of fossil fuel energy generation with renewable energy generation?


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.