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Bridging climate science, citizens, and policy


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Climate and Energy Links – 31Aug2014

Some goodies I’ve marked but don’t have time to go into detail on—

The recent slowdown in near-surface global temperature rise has been tackled by many researchers.  This is what research science is all about: proposing hypotheses to explain phenomena.  None of the hypotheses offered can, by themselves, explain all of the slowdown.  They are likely co-occurring, which is one reason why pinning the exact cause is so challenging.  The most recent is that the Atlantic Meridional Overturning Circulation is transporting upper-oceanic heat to intermediate depths, where satellites and surface observations cannot detect it.  This theory is in line with separate theories that Pacific circulation is doing much the same thing.  I myself now think the Pacific is probably the largest contributor to heat transport from the surface to ocean depth.  GHG concentrations remain higher than at any point in the past 800,00 years (or more).  Their radiative properties are not changing – which means they continue to re-radiate longwave energy back toward the Earth’s surface.  That energy is going somewhere in the Earth’s climate system because we know it isn’t escaping to space.  This process is hypothesized to last another 15-20 years – whether in the Pacific or Atlantic or both.

Some decent science gets written sloppily by an outfit that normally does  a pretty good job of writing: meteorological organizations across the world continue to say there is a relatively high chance that 2014 will feature an El Niño.  Unfortunately, that’s not exactly how it’s reported in this article:

After initially predicting with 90 per cent certainty we’d see an El Niño by the end of the year, forecasters began scaling back their predictions earlier this month.

Number one – that’s not what forecasters predicted and the difference is important.  Forecasters predicted that there was a 90% probability that an El Niño would develop.  Probability and certainty are two very separate concepts – which is why we use two different words to describe two different things.  You’ll notice the forecasters didn’t predict either a 100% probability or with 100% certainty an El Niño would develop.  90% probability is very high, but there remained a 10% probability an El Niño wouldn’t develop.  And so far, it hasn’t.  It is still likelier than not that one will develop, but the chances that one won’t develop are higher now than in June.  A number of factors have not yet come together to initiate an El Niño event.  If they don’t come together, an El Niño likely won’t form this year.  But a blog devoted to climate science and energy policy should know how to write about these topics better than they did in this case.  Oh, and to all the climate activists who bet the farm an El Niño would definitely form this year and prove all those skeptics wrong … you look just as foolish as the skeptics screaming about their closely-held beliefs.  Scientists in particular should know better: wait until groups make observations about El Niño.  Predicting them remains much trickier than weather forecasting.  Because the next time you shout wolf…

On another note, a cool infographic:

Which means 50% of the U.S. population scattered across the entire rest of this big country is trying to tell urbanites how to lead their lives.  Something about tyranny and devotion to small government comes to mind…

Then,

This is certainly a small piece of good news.  Now the reality check: these numbers need to be orders of magnitude higher to keep global temperatures below 2C above the recent mean.  Furthermore, they need to be higher in every country.  China’s deployment of renewable energy dwarfs the U.S.’s and even that isn’t enough.  This is good, but we need much better.

More of this while we’re at it: dialogue between people and climate scientists.

Okay, that’s it.  I have my own paper to write.  Back to it.


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NASA & NOAA: April 2014 Warmest Globally On Record

According to data released by NASA and NOAA this month, April was the warmest April globally on record.  Here are the data for NASA’s analysis; here are NOAA data and report.  The two agencies have different analysis techniques, which in this case resulted in slightly different temperature anomaly values but the same overall rankings within their respective data sets.  The analyses result in different rankings in most months.  The two techniques do provide a check on one another and confidence for us that their results are robust.  At the beginning, I will remind readers that the month-to-month and year-to-year values and rankings matter less than the long-term climatic warming.  Weather is the dominant factor for monthly and yearly conditions, not climate.

The details:

April’s global average temperature was 0.73°C (1.314°F) above normal (14°C; 1951-1980), according to NASA, as the following graphic shows.  The past three months have a +0.63°C temperature anomaly.  And the latest 12-month period (May 2013 – Apr 2014) had a +0.62°C temperature anomaly.  The time series graph in the lower-right quadrant shows NASA’s 12-month running mean temperature index.  The 2010-2012 downturn was largely due to the last La Niña event (see below for more).  Since then, ENSO conditions returned to a neutral state (neither La Niña nor El Niño).  As previous anomalously cool months fell off the back of the running mean, the 12-month temperature trace tracked upward again throughout 2013 and 2014.

 photo NASA-Temp_Analysis_20140430_zps82150da6.gif

Figure 1. Global mean surface temperature anomaly maps and 12-month running mean time series through April 2014 from NASA.

According to NOAA, April’s global average temperatures were +0.77°C (1.386°F) above the 20th century average of 13.7°C (56.7°F).  NOAA’s global temperature anomaly map for April (duplicated below) shows where conditions were warmer and cooler than average during the month.

 photo NOAA-Temp_Analysis_201404_zps92d3f6cb.gif

Figure 2. Global temperature anomaly map for August 2013 from NOAA.

The two different analyses’ importance is also shown by the preceding two figures.  Despite differences in specific global temperature anomalies, both analyses picked up on the same spatial temperature patterns and their relative strength.

Influence of ENSO

 photo NinoSSTAnom20140501_zpsc925f282.gif

Figure 3. Time series of weekly SST data from NCEP (NOAA).  The highest interest region for El Niño/La Niña is `NINO 3.4` (2nd time series from top).

There has been neither El Niño nor La Niña in the past couple of years.  This ENSO-neutral phase is common.  As you can see in the NINO 3.4 time series (2nd from top in Figure 3), Pacific sea surface temperatures were relatively cool in January through March, then quickly warmed.  This switch occurred because normal easterly winds (blowing toward the west) across the equatorial Pacific relaxed and two significant westerly wind bursts occurred in the western Pacific.  These anomalous winds generated an eastward moving Kelvin wave, which causes downwelling and surface mass convergence.  Warm SSTs collect along the equator as a result.  These Kelvin waves eventually crossed the entire Pacific Ocean, as Figure 4 shows.

 photo PacifcOcEqTAnomaly20140523_zpsff7554f1.gif

Figure 4.  Sub-surface Pacific Ocean temperature anomalies from Jan-Apr 2014.  Anomalously cool eastern Pacific Ocean temperatures in January gave way to anomalously warm temperatures by April.  Temperatures between 80W and 100W warmed further since April 14.

The Climate Prediction Center announced an El Niño Watch earlier this year.  The most recent update says the chances of an El Niño during the rest of 2014 exceeds 65%.  There is no reliable prediction of the potential El Niño’s strength at this time.  Without another westerly wind burst, an El Niño will likely not be very strong.  Even moderate strength El Niños impact global weather patterns.

An important detail is whether the potential 2014 El Niño will be an Eastern or Central Pacific El Niño (see figure below).  Professor Jin-Yi Yu, along with colleagues, first proposed the difference in a 2009 Journal of Climate paper.  More recently, Yu’s work suggested a recent trend toward Central Pacific El Niños influenced the frequency and intensity of recent U.S. droughts.  This type of El Niño doesn’t cause global record temperatures, but still impacts atmospheric circulations and the jet stream, which impacts which areas receive more or less rain.  If the potential 2014 El Niño is an Eastern Pacific type, we can expect monthly global mean temperatures to spike and the usual precipitation anomalies commonly attributed to El Niño.

 photo EastvsCentralPacificENSOschematic_zps08856e81.jpg

Figure 5. Schematic of Central-Pacific ENSO versus Eastern-Pacific ENSO as envisioned by Dr. Jin-Yi Yu at the University of California – Irvine.

If an El Niño does occur later in 2014, it will mask some of the deep ocean heat absorption by releasing energy back to the atmosphere.  If that happens, the second half of 2014 and the first half of 2015 will likely set global surface temperature records.  2014, 2015, or both could set the all-time global mean temperature record (currently held by 2010).  Some scientists recently postulated that an El Niño could also trigger a shift from the current negative phase of the Interdecadal Pacific Oscillation (IPO; or PDO for just the northern hemisphere) to a new positive phase.  This would be similar in nature, though different in detail, as the shift from La Niña or neutral conditions to El Niño.  If this happens, the likelihood of record hot years would increase.  I personally do not believe this El Niño will shift the IPO phase.  I don’t think this El Niño will be strong enough and I don’t think the IPO is in a conducive state for a switch to occur.

The “Hiatus”

Skeptics have pointed out that warming has “stopped” or “slowed considerably” in recent years, which they hope will introduce confusion to the public on this topic.  What is likely going on is quite different: since an energy imbalance exists (less energy is leaving the Earth than the Earth is receiving; this is due to atmospheric greenhouse gases) and the surface temperature rise has seemingly stalled, the excess energy is going somewhere.  The heat has to go somewhere – energy doesn’t just disappear.  That somewhere is likely the oceans, and specifically the deep ocean (see figure below).  Before we all cheer about this (since few people want surface temperatures to continue to rise quickly), consider the implications.  If you add heat to a material, it expands.  The ocean is no different; sea-levels are rising in part because of heat added to it in the past.  The heat that has entered in recent years won’t manifest as sea-level rise for some time, but it will happen.  Moreover, when the heated ocean comes back up to the surface, that heat will then be released to the atmosphere, which will raise surface temperatures as well as introduce additional water vapor due to the warmer atmosphere.  Thus, the immediate warming rate might have slowed down, but we have locked in future warming (higher future warming rate).

 photo Ocean_heat_content_balmaseda_et_al_zps23184297.jpg

Figure 6. Recent research shows anomalous ocean heat energy locations since the late 1950s.  The purple lines in the graph show how the heat content of the whole ocean has changed over the past five decades. The blue lines represent only the top 700 m and the grey lines are just the top 300 m.  Source: Balmaseda et al., (2013)

You can see in Figure 6 that the upper 300m of the world’s oceans accumulated less heat during the 2000s (5*10^22 J) than during the 1990s.  In contrast, accumulated heat greatly increased in ocean waters between 300m and 700m during the 2000s (>10*10^22 J).  We cannot and do not observe the deep ocean with great frequency.  We do know from frequent and reliable observations that the sea surface and relatively shallow ocean did not absorb most of the heat in the past decade.  We also know how much energy came to and left the Earth from satellite observations.  If we know how much energy came in, how much left, and how much the land surface and shallow ocean absorbed, it is a relatively straightforward computation to determine how much energy likely remains in the deep ocean.

Discussion

The fact that April 2014 was the warmest on record despite a negative IPO and a neutral ENSO is eye-opening.  I think it highlights the fact that there is an even lower frequency signal underlying the IPO, ENSO, and April weather: anthropogenic warming.  That signal is not oscillatory, it is increasing at an increasing rate and will continue to do so for decades to centuries.  The length of time that occurs and its eventual magnitude is dependent on our policies and activities.  We continue to emit GHGs at or above the high-end of the range simulated by climate models.  Growth in fossil fuel use at the global scale continues.  This growth dwarfs any effect of a switch to energy sources with lower GHG emissions.  I don’t think that will change during the next 15 years, which would lock us into the warmer climate projections through most of the rest of the 21st century.  The primary reason for this is the scale of humankind’s energy infrastructure.  Switching from fossil fuels to renewable energy will take decades.  Acknowledging this isn’t defeatist or pessimistic; it is I think critical in order to identify appropriate opportunities and implement the type and scale of policy responses to encourage that switch.


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More Discussion on Warming “Hiatus”

After a lengthy absence during which I studied for the most challenging mental exercise I’ve ever faced – departmental Comprehensive Exams – I’m going to kick off 2014 with another discussion about the early 21-century warming “hiatus”.  There is good reason for this: the climate is complex and understanding the individual parts remains as active research, to say nothing of how those parts interact, which adds complexity upon complexity.  It also gets me back in the swing of writing again.

The motivation for this piece is a new paper, “An apparent hiatus in global warming?”.  Here are important parts of the abstract (you can read the entire abstract at the link):

Global warming first became evident beyond the bounds of natural variability in the 1970s, but increases in global mean surface temperatures have stalled in the 2000s.  Increases in atmospheric greenhouse gases, notably carbon dioxide, create an energy imbalance at the top-of-atmosphere (TOA) even as the planet warms to adjust to this imbalance, which is estimated to be 0.5–1 W m−2 over the 2000s. [...] An energy imbalance is manifested not just as surface atmospheric or ground warming but also as melting sea and land ice, and heating of the oceans. More than 90% of the heat goes into the oceans and, with melting land ice, causes sea level to rise. For the past decade, more than 30% of the heat has apparently penetrated below 700 m depth that is traceable to changes in surface winds mainly over the Pacific in association with a switch to a negative phase of the Pacific Decadal Oscillation (PDO) in 1999. Surface warming was much more in evidence during the 1976–1998 positive phase of the PDO, suggesting that natural decadal variability modulates the rate of change of global surface temperatures while sea-level rise is more relentless. Global warming has not stopped; it is merely manifested in different ways.

Some important notes here.  Greenhouse gases consistently increased during the 20th century, with increasing rates in recent decades.  But how do those GHGs affect the climate?  They emit radiation back towards the Earth’s surface, but it takes time for that radiation to manifest as detectable heat.  It’s a slowly accumulating effect, which other processes and phenomena influence.  To be more specific, the Earth’s surface temperature (land and ocean) shows the effect of that slow accumulation decades later.  This decade’s surface temperatures are largely the result of GHG concentrations from 20-30 years ago.  Which means that today’s concentrations will largely affect surface temperatures 20+ years from now, not today.

Let’s take a look at one of the study’s graph’s – global mean surface temperature anomalies from 1850-2012.

 photo GlobalMeanTemperature-TrenberthampFasullo2014_zps15374d73.jpg

Figure 1. Global mean surface temperature anomaly (1850-2012; Trenberth & Fasullo) as observed by the four most used datasets.

After a rapid rise in the 2nd half of the 20th century, it does indeed appear as though warming has paused since 2000.  But I just wrote that GHG concentrations increased throughout the 20th century and into the 21st.  So why does the “pause” appear in the temperature record?  Because of other climate processes, in this case natural processes that I’ve also written about (see here and here).

 photo Global12-monthrunningmeansurfaceTanomaly-TrenberthampFasullo20140113_zps3f9a0298.jpg

Figure 2.  Global mean surface temperature anomaly (12-month running mean) with El Nino (orange) and La Nina (blue) events highlighted.

Figure 2 shows how the biggest high-frequency climate oscillation impacts global mean surface temperature anomalies.  Following the record-setting 1997-1998 El Niño, annual temperature anomalies stayed primarily within +0.6 to +0.7C.  The paper hypothesizes that the 97-98 El Niño initiated a change in longer-term oscillations – namely the Pacific Decadal Oscillation (related to the Interdecadal Pacific Oscillation, which impacts my own research).

 photo PDOIndex1950-2013TrenberthampF20140113_zpse6e432fa.jpg

Figure 3. Time series of Pacific Decadal Oscillation Index (1950-2013).

Phases characterize the index: warm (1977-1998) and cool (1948-1976 & 1999-current).  Look back at Figure 1 and the PDO’s effect on global mean surface temperature anomalies is clear: less warming is present during the cool phases and more warming during the warm phase.  Now, this analysis is limited by the relatively short observational period, but researchers are teasing out PDO effects from paleoclimatic studies going back hundreds of years.  The PDO’s cool phase is characterized by cooler than normal eastern Pacific sea surface temperatures.  Averaged out over 10-30 years, the cool phase looks remarkably similar to La Nina.  Conversely for the warm phase, the eastern Pacific is much warmer than normal and resembles a long-term El Niño.

Now for some complexity.  The short-lived El Niño/La Niña events occur on top of the PDO signal.  So the Earth can have a long-term cool phase (negative PDO) and have both warm and cool ENSO phases (El Niño/La Niña) on annual to interannual timescales.  Look at Figure 2 again to see the additive impacts.  The 1997-98 El Niño occurred at the end of the last PDO warm phase, but also during a warming trend whose timescale exceeds the PDO’s (anthropogenic climate change).  Four recent La Niñas occurred during the current negative (cool) PDO phase within the past 10 years (see Figure 2).  Is it any wonder then that global mean surface temperatures haven’t risen at the same rate they did during the 1977-1998 period?

So what does this mean going forward?  First of all, I disagree with the 2nd half of Trenberth’s statement: “This year or later, it’s possible that El Niño will occur again in the Pacific. Will that trigger another change in the PDO, that in turn could trigger a resurgence in global surface temperature warming? Only time will tell, Trenberth explained.”  Given the historical PDO record, I seriously doubt the next El Niño will switch the PDO phase back to positive (warm).  The PDO has been in its current negative phase for only 14 years or so now.  It’s more likely that this negative phase will continue for at least the next 5 years.  I wouldn’t be surprised if it continued for the next 10-15 years.  Which doesn’t mean global temperatures won’t rise; it means they would likely rise at a slower rate than they did during the late 20th century.  When the next PDO positive phase occurs, global temperatures will likely show that shift by increasing at a faster rate than during the past 15 years.

Lastly, just because the Earth’s surface hasn’t warmed quite as much as expected in the past 10-15 years doesn’t mean the heat disappeared.  What you heard as a kid was true: energy cannot be destroyed, only changed.  The heat energy emitted by GHGs during the past 30 years went to a place humans don’t measure very well or very much: the deep ocean, as this graph shows:

 photo Ocean_heat_content_balmaseda_et_al_zps23184297.jpg

Figure 4.  Anomalous ocean heat energy locations since the late 1950s.  The purple lines in the graph show how the heat content of the whole ocean has changed over the past five decades. The blue lines represent only the top 700 m and the grey lines are just the top 300 m.  Source: Balmaseda et al., (2013)

This graph shows that during the global warming “pause” period (1999-current), the ocean below 700m absorbed the majority of the heat of the entire ocean system.  You can also quite clearly see the anomalous heat content of recent years.  This increased oceanic heat content will manifest itself in upcoming decades and centuries.  Sea levels will rise because warmer substances occupy more volume than cooler substances.  That effect alone threatens the majority of the Earth’s human population.  It also threatens frozen water reservoirs: the globe’s ice caps.  As they melt at an increasing rate throughout this century, global sea levels will rise even further.  As warmer deep ocean water returns to the surface and interacts with a warmer atmosphere which can hold more moisture and therefore heat, the heat will eventually transfer to the atmosphere where we can more regularly measure it.  So aside from the natural climate oscillations discussed above (ENSO & PDO), much of this heat will affect us at some point.

Will we be ready for those impacts?  Contemporary examples suggest no, but municipalities are taking already visible threats more seriously every day.  Those local efforts will guide actions at higher levels of government and society.


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NASA & NOAA: August 2013 4th Warmest Globally On Record

According to data released by NASA and NOAA this month, August was the 4th warmest August globally on record.  Here are the data for NASA’s analysis; here are NOAA data and report.  The two agencies have different analysis techniques, which in this case resulted in different temperature anomaly values but the same overall rankings within their respective data sets.  The analyses result in different rankings in most months.  The two techniques do provide a check on one another and confidence for us that their results are robust.  At the beginning, I will remind readers that the month-to-month and year-to-year values and rankings matter less than the long-term climatic warming.  Monthly and yearly conditions changes primarily by the weather, which is not climate.

The details:

August’s global average temperature was 0.62°C (1.12°F) above normal (1951-1980), according to NASA, as the following graphic shows.  The past three months have a +0.58°C temperature anomaly.  And the latest 12-month period (Aug 2012 – Jul 2013) had a +0.59°C temperature anomaly.  The time series graph in the lower-right quadrant shows NASA’s 12-month running mean temperature index.  The 2010-2012 downturn was largely due to the latest La Niña event (see below for more) that ended early last summer.  Since then, ENSO conditions returned to a neutral state (neither La Niña nor El Niño).  Therefore, as previous anomalously cool months fall off the back of the running mean, and barring another La Niña, the 12-month temperature trace should track upward again throughout 2013.

 photo NASA-Temp_Analysis_20130831_zps3ff2a250.gif

Figure 1. Global mean surface temperature anomaly maps and 12-month running mean time series through August 2013 from NASA.

According to NOAA, April’s global average temperatures were 0.62°C (1.12°F) above the 20th century average of 15.6°C (60.1°F).  NOAA’s global temperature anomaly map for August (duplicated below) shows where conditions were warmer and cooler than average during the month.

 photo NOAA-Temp_Analysis_201308_zpsf2f24a41.gif

Figure 2. Global temperature anomaly map for August 2013 from NOAA.

The two different analyses’ importance is also shown by the preceding two figures.  Despite differences in specific global temperature anomalies, both analyses picked up on the same temperature patterns and their relative strength.

 photo NinoSSTAnom20130924_zps74ba969c.gif

Figure 3. Time series of weekly SST data from NCEP (NOAA).  The highest interest region for El Niño/La Niña is NINO 3.4 (2nd time series from top).

The last La Niña event hit its highest (most negative) magnitude more than once between November 2011 and February 2012.  Since then, tropical Pacific sea-surface temperatures peaked at +0.8 (y-axis) in September 2012.  You can see the effect on global temperatures that the last La Niña had via this NASA time series.  Both the sea surface temperature and land surface temperature time series decreased from 2010 (when the globe reached record warmth) to 2012.  Recent ENSO events occurred at the same time that the Interdecadal Pacific Oscillation entered its most recent negative phase.  This phase acts like a La Niña, but its influence is smaller than La Niña.  So natural, low-frequency climate oscillations affect the globe’s temperatures.  Underlying these oscillations is the background warming caused by humans, which we detect by looking at long-term anomalies.  Despite these recent cooling influences, temperatures were still top-10 warmest for a calendar year (2012) and during individual months, including August 2013.

Skeptics have pointed out that warming has “stopped” or “slowed considerably” in recent years, which they hope will introduce confusion to the public on this topic.  What is likely going on is quite different: since an energy imbalance exists (less energy is leaving the Earth than the Earth is receiving; this is due to atmospheric greenhouse gases) and the surface temperature rise has seemingly stalled, the excess energy is going somewhere.  The heat has to be going somewhere – energy doesn’t just disappear.  That somewhere is likely the oceans, and specifically the deep ocean (see figure below).  Before we all cheer about this (since few people want surface temperatures to continue to rise quickly), consider the implications.  If you add heat to a material, it expands.  The ocean is no different; sea-levels are rising in part because of heat added to it in the past.  The heat that has entered in recent years won’t manifest as sea-level rise for some time, but it will happen.  Moreover, when the heated ocean comes back up to the surface, that heat will then be released to the atmosphere, which will raise surface temperatures as well as introduce additional water vapor due to the warmer atmosphere.  Thus, the immediate warming rate might have slowed down, but we have locked in future warming (higher future warming rate).

 photo Ocean_heat_content_balmaseda_et_al_zps23184297.jpg

Figure 4. New research that shows anomalous ocean heat energy locations since the late 1950s.  The purple lines in the graph show how the heat content of the whole ocean has changed over the past five decades. The blue lines represent only the top 700 m and the grey lines are just the top 300 m.  Source: Balmaseda et al., (2013)

Paying for recovery from seemingly localized severe weather and climate events is and always will be more expensive than paying to increase resilience from those events.  As drought continues to impact the US, as Arctic ice continues its long-term melt, as storms come ashore and impacts communities that are not prepared for today’s high-risk events (due mostly to poor zoning and destruction of natural protections), economic costs will accumulate in this and in future decades.  It is up to us how many costs we subject ourselves to.  As President Obama begins his second term with climate change “a priority”, he tosses aside the most effective tool available and most recommended by economists: a carbon tax.  Every other policy tool will be less effective than a Pigouvian tax at minimizing the actions that cause future economic harm.  It is up to the citizens of this country, and others, to take the lead on this topic.  We have to demand common sense actions that will actually make a difference.

But be forewarned: even if we take action today, we will still see more warmest-ever La Niña years, more warmest-ever El Niño years, more drought, higher sea levels, increased ocean acidification, more plant stress, and more ecosystem stress.  The biggest difference between efforts in the 1980s and 1990s to scrub sulfur and CFC emissions and future efforts to reduce CO2 emissions is this: the first two yielded an almost immediate result.  It will take decades to centuries before CO2 emission reductions produce tangible results humans can see.  That is part of what makes climate change such a wicked problem.


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NASA & NOAA: April 2013 13th Warmest Globally On Record

According to data released by NASA and NOAA last week, April was the 13th warmest April globally on record.  Here are the data for  NASA’s analysis; here are NOAA data and report.  The two agencies have slightly different analysis techniques, which in this case resulted in different temperature anomaly values but the same overall rankings.  Most months, the analyses result in different rankings.  The two techniques do provide a check on one another and confidence for us that their results are robust.

The details:

April’s global average temperatures were 0.50°C (0.9°F) above normal (1951-1980), according to NASA, as the following graphic shows.  The past three months have a +0.53°C temperature anomaly.  And the latest 12-month period (Apr 2012 – Mar 2013) had a +0.59°C temperature anomaly.  The time series graph in the lower-right quadrant shows NASA’s 12-month running mean temperature index.  The 2010-2012 downturn was largely due to the latest La Niña event (see below for more) that ended early last summer.  Since then, ENSO conditions returned to a neutral state (neither La Niña nor El Niñ0).  Therefore, as previous anomalously cool months fall off the back of the running mean, and barring another La Niña, the 12-month temperature trace should track upward again throughout 2013.

 photo NASA-Temp_Analysis_20130430_zpsd93c9d48.gif

Figure 1. Global mean surface temperature anomaly maps and 12-month running mean time series through April 2013 from NASA.

According to NOAA, April’s global average temperatures were 0.52°C (0.94°F) above the 20th century mean of 13.7°C (56.7°F).  NOAA’s global temperature anomaly map for April (duplicated below) shows where conditions were warmer and cooler than average during the month.

 photo NOAA-Temp_Analysis_201304_zps204a8f35.gif

Figure 2. Global temperature anomaly map for January 2013 from NOAA.

The two different analyses’ importance is also shown by the preceding two figures.  Despite differences in specific global temperature anomalies, both analyses picked up on the same temperature patterns and their relative strength.

Both analyses show much cooler than normal conditions over most of North America, Europe, and northeast Asia.  As I’ve discussed elsewhere, this is in response to the abnormal jet stream.  Large, unmoving high pressure centers blocked the jet stream at different locations in the Northern Hemisphere multiple times this winter and spring.  The jet stream therefore assumed a high amplitude pattern where the trough and ridge axes were tens of degrees of latitude apart from one another.  When this happens, very cold air is pulled southward and warm air is pulled northward (look at central Eurasia).  In April 2013, the specific position of the high pressure centers caused cold air to spill southward over land as opposed to over the oceans.  These cold air outbreaks were an advantage for the US in that severe storms were unable to form.  This situation obviously broke down in the past couple of weeks and we have correspondingly seen devastating severe weather outbreaks across the south-central US.

During the second half of last year, a ENSO-neutral state (neither El Niño nor La Niña) began, which continues to this day:

 photo NinoSSTAnom20130501_zpsf742a7c0.gif

Figure 3. Time series of weekly SST data from NCEP (NOAA).  The highest interest region for El Niño/La Niña is NINO 3.4 (2nd time series from top).

The last La Niña event hit its highest (most negative) magnitude more than once between November 2011 and February 2012.  Since then, tropical Pacific sea-surface temperatures peaked at +0.8 (y-axis) in September 2012.  You can see the effect on global temperatures that the last La Niña had via this NASA time series.  Both the sea surface temperature and land surface temperature time series decreased from 2010 (when the globe reached record warmth) to 2012.  So a natural, low-frequency climate oscillation affected the globe’s temperatures during the past couple of years.  Underlying that oscillation is the background warming caused by humans.  And yet temperatures were still in the top-10 warmest for a calendar year (2012) and individual months, including through March 2013, in recorded history.  We ascribe a certain status to top-10 events.  April 2013 obviously missed the top-10 threshold, but it remains close to that level of anomalous warmth.  However, the difference in temperature magnitude between the 10th and 13th warmest Aprils is measured in tenths of a degree.

Skeptics have pointed out that warming has “stopped” or “slowed considerably” in recent years, which they hope will introduce confusion to the public on this topic.  What is likely going on is quite different: since an energy imbalance exists (less outgoing energy than incoming energy due to atmospheric greenhouse gases) and the surface temperature rise has seemingly stalled, the excess energy is going somewhere.  That somewhere is likely the oceans, and specifically the deep ocean (see figure below).  Before we all cheer about this (since few people want surface temperatures to continue to rise quickly), consider the implications.  If you add heat to a material, it expands.  The ocean is no different; sea-levels are rising in part because of heat added to it in the past.  The heat that has entered in recent years won’t manifest as sea-level rise for some time, but it will happen.  Moreover, when the heated ocean comes back up to the surface, that heat will then be released to the atmosphere, which will raise surface temperatures as well as introduce additional water vapor due to the warmer atmosphere.  Thus, the immediate warming rate might have slowed down, but we have locked in future warming (higher future warming rate).

 photo Ocean_heat_content_balmaseda_et_al_zps23184297.jpg

Figure 4. New research that shows anomalous ocean heat energy locations since the late 1950s.  The purple lines in the graph show how the heat content of the whole ocean has changed over the past five decades. The blue lines represent only the top 700 m and the grey lines are just the top 300 m.  Source: Balmaseda et al., (2013)

Paying for recovery from seemingly localized severe weather and climate events is and always will be more expensive than paying to increase resilience from those events.  As drought continues to impact US agriculture, as Arctic ice continues to melt to new record lows, as storms come ashore and impacts communities that are not prepared for today’s high-risk events (due mostly to poor zoning and destruction of natural protections), economic costs will accumulate in this and in future decades.  It is up to us how many costs we subject ourselves to.  As President Obama begins his second term with climate change “a priority”, he tosses aside the most effective tool available and most recommended by economists: a carbon tax.  Every other policy tool will be less effective than a Pigouvian tax at minimizing the actions that cause future economic harm.  It is up to the citizens of this country, and others, to take the lead on this topic.  We have to demand common sense actions that will actually make a difference.  But be forewarned: even if we take action today, we will still see more warmest-ever La Niña years, more warmest-ever El Niño years, more drought, higher sea levels, increased ocean acidification, more plant stress, and more ecosystem stress.  The biggest difference between efforts in the 1980s and 1990s to scrub sulfur and CFC emissions and future efforts to reduce CO2 emissions is this: the first two yielded an almost immediate result while it will take decades to centuries before CO2 emission reductions produce tangible results humans can see.  That is part of what makes climate change such a wicked problem.


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NASA & NOAA: March 2013 9th, 10th Warmest Globally On Record

According to data released by NOAA, March was the 10th warmest globally on record.  Here are the NOAA data and report.  NASA also released their suite of graphics, but their surface temperature data page is down today, so I cannot relay how NASA’s March temperature compares to historical Marches.  Once their site is back up, I will update this post.  [Update: NASA’s analysis resulted in their 9th warmest March on record.  Here are the data for  NASA’s analysis.] The two agencies have slightly different analysis techniques, which in this case resulted in not only different temperature anomaly values but somewhat different rankings as well.  The two techniques provide a check on one another and confidence for us.

The details:

March’s global average temperatures were 0.59°C (1.062°F) above normal (1951-1980), according to NASA, as the following graphic shows.  The past three months have a +0.57°C temperature anomaly.  And the latest 12-month period (Apr 2012 – Mar 2013) had a +0.60°C temperature anomaly.  The time series graph in the lower-right quadrant shows NASA’s 12-month running mean temperature index.  The recent downturn (2010-2012) was largely due to the latest La Niña event (see below for more) that ended early last summer.  Since then, ENSO conditions returned to a neutral state (neither La Niña nor El Niñ0).  Therefore, as previous anomalously cool months fall off the back of the running mean, and barring another La Niña, the 12-month temperature trace should track upward again throughout 2013.

 photo NASA-Temp_Analysis_20130331_zps2e2b340a.gif

Figure 1. Global mean surface temperature anomaly maps and 12-month running mean time series through March 2013 from NASA.

According to NOAA, March’s global average temperatures were 0.58°C (1.044°F) above the 20th century mean of 12.7°C (54.9°F).  NOAA’s global temperature anomaly map for March (duplicated below) shows where conditions were warmer than average during the month.

 photo GlobalTemperatureAnomalyMap201303_zpsf432fd9b.gif

Figure 2. Global temperature anomaly map for March 2013 from NOAA.

The two different analyses’ importance is also shown by the preceding two figures.  Despite small differences in specific global temperature anomalies, both analyses picked up on the same temperature patterns and their relative strength.

The very warm conditions found over Greenland are a concern.  Greenland was warmer than average during more months in recent history than not.  In contrast to 2012, northern Eurasian temperatures were much cooler than normal.  This is likely a temporary, seasonal effect.  Long-term temperatures over much of this region continue to rise at among the fastest rate for any region on Earth.

The NASA and NOAA surface temperature maps correlate well with the 500-mb height pressure anomalies, as seen in this graph:

 photo NOAA500hPaanomalymap201303_zps6d024aed.gif

Figure 3. 500-mb heights (white contours) and anomalies (m; color contours) during March 2013.

Note the correspondence between the height map and the NASA & NOAA surface temperature maps: lower heights (negative height anomalies) present over the North Atlantic and northern Eurasia overlay the cold surface temperature anomalies at the surface.  Similarly, warm surface temperature anomalies are located under the positive 500-mb height anomalies.

These temperature observations are of interest for the following reason: the globe came out of a moderate La Niña event in the first half of last year.  During the second half of the 2012 and the first part of 2013, we remained in a ENSO-neutral state (neither El Niño nor La Niña):

 photo NinoSSTAnom20130401_zpsf59ac6f7.gif

Figure 4. Time series of weekly SST data from NCEP (NOAA).  The highest interest region for El Niño/La Niña is NINO 3.4 (2nd time series from top).

The last La Niña event hit its highest (most negative) magnitude more than once between November 2011 and February 2012.  Since then, tropical Pacific sea-surface temperatures peaked at +0.8 (y-axis) in September 2012.  You can see the effect on global temperatures that the last La Niña had via this NASA time series.  Both the sea surface temperature and land surface temperature time series decreased from 2010 (when the globe reached record warmth) to 2012.  So a natural, low-frequency climate oscillation affected the globe’s temperatures during the past couple of years.  Underlying that oscillation is the background warming caused by humans.  And yet temperatures were still in the top-10 warmest for a calendar year (2012) and individual months, including March 2013, in recorded history.

Skeptics have pointed out that warming has “stopped” in recent years (by comparing recent temperatures to the 1998 maximum which was heavily influenced by a strong El Niño even), which they hope will introduce confusion to the public on this topic.  What is likely going on is quite different: a global annual energy imbalance exists (less outgoing energy than incoming energy).  If the surface temperature rise has seemingly stalled, the excess energy is going somewhere.  That somewhere is likely the oceans, and specifically the deep ocean (see the figures below).  Before we all cheer about this (since few people want surface temperatures to continue to rise quickly), consider the implications.  If you add heat to a material, it expands.  The ocean is no different; sea-levels are rising in part because of heat added to it in the past.  The heat that has entered in recent years won’t manifest as sea-level rise for some time, but it will happen.  Moreover, when the heated ocean comes back up to the surface, that heat will then be released to the atmosphere, which will raise surface temperatures as well as introduce additional water vapor.  Thus, the short-term warming rate might have slowed down, but we have locked in future warming (higher future warming rate) as well as future climate effects.

 photo Total-Heat-Content.gif

Figure 5. Total global heat content anomaly from 1950-2004. An overwhelming majority of energy went to the global oceans.

 photo Ocean_heat_content_balmaseda_et_al_zps23184297.jpg

Figure 6. New research that shows anomalous ocean heat energy location since the late 1950s.  The purple lines in the graph show how the heat content of the whole ocean has changed over the past five decades. The blue lines represent only the top 700 m and the grey lines are just the top 300 m.  Source: Balmaseda et al., (2013)

Balmaseda et al.’s work demonstrates the transport of anomalous energy through the depth of the global oceans.  Note that the grey lines’ lack of significant change from 2004-2008 (upper 300m).  Observations of surface temperature include the very top part of this 300m layer.  Since the layer hasn’t changed much, neither have surface temperature readings.  Note the rapid increase in heat content within the top 700m.  Given the lack of increase in the top 300m, the 300-700m layer heat content must have increased.  By the same logic, the rapid growth in heat content throughout the depth of the ocean, which did not stall post-2004, provides evidence for anomalous heat location.  You can also see the impact of major volcanic eruptions on ocean heat content: less incoming solar radiation means less absorbed heat.

A significant question for climate scientists is this: are climate models capable of picking up this heat anomaly signal and do they show a similar trend?  If they aren’t, then their projections of surface temperature change is likely to be incorrect since the heat is warming the abyssal ocean and not the land and atmosphere in the 2000s and 2010s.  If they aren’t, climate policy is also impacted.  Instead of warmer surface temperatures (and effects on drought, agriculture, and health to name just a few), anomalous ocean heat content will impact coastal communities more than previously thought.  Consider the implications of that in addition to the AR4′s lack of consideration of land-based ice melt: sea level projections could be too conservative.

That said, it is also a fair question to ask whether today’s climate policies are sufficient for today’s climate.  In many cases, I would say  they aren’t sufficient.  Paying for recovery from seemingly localized severe weather and climate events is and always will be more expensive than paying to increase resilience from those events.  As drought continues to impact US agriculture, as Arctic ice continues to melt to new record lows, as storms come ashore and impacts communities that are not prepared for today’s high-risk events (due mostly to poor zoning and destruction of natural protections), economic costs will accumulate in this and in future decades.  It is up to us how many costs we subject ourselves to.

As President Obama began his second term with climate change “a priority”, he tosses aside the most effective tool available and most recommended by economists: a carbon tax.  Every other policy tool will be less effective than a Pigouvian tax at minimizing the actions that cause future economic harm.  It is up to the citizens of this country, and others, to take the lead on this topic.  We have to demand common sense actions that will actually make a difference.  But be forewarned: even if we take action today, we will still see more warmest La Niña years, more warmest El Niño years, more drought, higher sea levels, increased ocean acidification, more plant stress, and more ecosystem stress.  The biggest difference between efforts in the 1980s and 1990s to scrub sulfur and CFC emissions and future efforts to reduce CO2 emissions is this: the first two yielded an almost immediate result while it will take decades before CO2 emission reductions produce tangible results humans can see.


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NASA & NOAA: January 2013 Was 6th, 9th Warmest Globally On Record

According to data released by NASA and NOAA last week, January was the 6th and 9th warmest January’s (respectively) globally on record.  Here are the data for  NASA’s analysis; here are NOAA data and report.  The two agencies have slightly different analysis techniques, which in this case resulted in not only different temperature anomaly values but somewhat different rankings as well.  The two techniques provide a check on one another and confidence for us.

The details:

January’s global average temperatures were 0.61°C (1.098°F) above normal (1951-1980), according to NASA, as the following graphic shows.  The warmest regions on Earth coincide with the locations where climate models have been projecting the most warmth will occur: high latitudes (especially within the Arctic Circle).  The past three months have a +0.58°C temperature anomaly.  And the latest 12-month period (Feb 2012 – Jan 2013) had a +0.58°C temperature anomaly.  The time series graph in the lower-right quadrant shows NASA’s 12-month running mean temperature index.  The recent downturn (2010-2012) is largely due to the latest La Niña event (see below for more) that ended early last summer.  Since then, ENSO conditions returned to a neutral state (neither La Niña nor El Niñ0).  Therefore, as previous anomalously cool months fall off the back of the running mean, and barring another La Niña, the 12-month temperature trace should track upward again in 2013.

 photo NASA-Temp_Analysis_20130131_zpsdfcedaac.gif

Figure 1. Global mean surface temperature anomaly maps and 12-month running mean time series through January 2013 from NASA.

According to NOAA, January’s global average temperatures were 0.54°C (0.97°F) above the 20th century mean of 14.0°C (57.2°F).  NOAA’s global temperature anomaly map for January (duplicated below) shows where conditions were warmer than average during the month.

 photo GlobalTemperatureAnomalyMap201301_zps05956f2c.gif

Figure 2. Global temperature anomaly map for January 2013 from NOAA.

The two different analyses’ importance is also shown by the preceding two figures.  Despite differences in specific global temperature anomalies, both analyses picked up on the same temperature patterns and their relative strength.

The very warm conditions found over Greenland and Alaska are a concern.  These areas were warmer than average during more months in recent history than not.  Additionally, Australia was much warmer than usual.  Indeed, Australia’s January average temperature was the highest on record: +2.28°C (4.10°F!) above the 1961–1990 average, besting the previous record set in 1932 by 0.11°C (0.20°F).  In contrast to 2012, Siberian temperatures were cooler than normal.  This is likely a temporary, seasonal effect.  Long-term temperatures over northern Siberia continue to rise at among the fastest rate for any region on Earth.

These observations are also worrisome for the following reason: the globe came out of a moderate La Niña event in the first half of the year.  During the second half of the year, we remained in a ENSO-neutral state (neither El Niño nor La Niña):

 photo NinoSSTAnom20130301_zps06ef6b19.gif

Figure 3. Time series of weekly SST data from NCEP (NOAA).  The highest interest region for El Niño/La Niña is NINO 3.4 (2nd time series from top).

The last La Niña event hit its highest (most negative) magnitude more than once between November 2011 and February 2012.  Since then, tropical Pacific sea-surface temperatures peaked at +0.8 (y-axis) in September 2012.  You can see the effect on global temperatures that the last La Niña had via this NASA time series.  Both the sea surface temperature and land surface temperature time series decreased from 2010 (when the globe reached record warmth) to 2012.  So a natural, low-frequency climate oscillation affected the globe’s temperatures during the past couple of years.  Underlying that oscillation is the background warming caused by humans.  And yet temperatures were still in the top-10 warmest for a calendar year (2012) and individual months, including January 2013, in recorded history.

Skeptics have pointed out that warming has “stopped” or “slowed considerably” in recent years, which they hope will introduce confusion to the public on this topic.  What is likely going on is quite different: since an energy imbalance exists (less outgoing energy than incoming energy) and the surface temperature rise has seemingly stalled, the excess energy is going somewhere.  That somewhere is likely the oceans, and specifically the deep ocean.  Before we all cheer about this (since few people want surface temperatures to continue to rise quickly), consider the implications.  If you add heat to a material, it expands.  The ocean is no different; sea-levels are rising because of heat added to it in the past.  The heat that has entered in recent years won’t manifest as sea-level rise for some time, but it will happen.  Moreover, when the heated ocean comes back up to the surface, that heat will then be released to the atmosphere, which will raise surface temperatures as well as additional water vapor.  Thus, the immediate warming rate might have slowed down, but we have locked in future warming (higher future warming rate).

In a previous post on global temperatures, I pointed a few things out and asked some questions.  The Conference of Parties summit produced no meaningful climate action (November 2012).  Countries agreed to have something on paper by 2015 and enacted by 2020.  If everything goes as planned (a huge assumption given the lack of historical progress), significant carbon reductions wouldn’t occur until later in the 2020s – too late to ensure <2°C warming by 2100.  If, as is much more likely, everything doesn’t go as planned, reductions wouldn’t occur until later than the 2020s.  Additional meetings are scheduled for this year, but I maintain my expectation that nothing meaningful will come from them.  The international process is ill-equipped to handle all the legitimate interest groups in one fell swoop.

Instead, actions that start locally and grow with time are more likely to address emissions and eventual warming and other climate change effects.  People started small-scale activities in cities around the world in recent years.  There are also regional and international carbon markets.  While most markets were poorly designed, lessons learned from the first generation can be used to make future generation markets more effective.  As these small-scale efforts grow and their effects combine, larger bodies will need to address differences between them so that they work for larger populations and markets.

Paying for recovery from seemingly localized severe weather and climate events is and always will be more expensive than paying to increase resilience from those events.  As drought continues to impact US agriculture, as Arctic ice continues to melt to new record lows, as storms come ashore and impacts communities that are not prepared for today’s high-risk events (due mostly to poor zoning and destruction of natural protections), economic costs will accumulate in this and in future decades.  It is up to us how many costs we subject ourselves to.  As President Obama begins his second term with climate change “a priority”, he tosses aside the most effective tool available and most recommended by economists: a carbon tax.  Every other policy tool will be less effective than a Pigouvian tax at minimizing the actions that cause future economic harm.  It is up to the citizens of this country, and others, to take the lead on this topic.  We have to demand common sense actions that will actually make a difference.  But be forewarned: even if we take action today, we will still see more warmest La Niña years, more warmest El Niño years, more drought, higher sea levels, increased ocean acidification, more plant stress, and more ecosystem stress.  The biggest difference between efforts in the 1980s and 1990s to scrub sulfur and CFC emissions and future efforts to reduce CO2 emissions is this: the first two yielded an almost immediate result while it will take decades before CO2 emission reductions produce tangible results humans can see.

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