See the Tabbed Pages for links to video tutorials, and a linked list of post titles grouped by topic.

This blog is expressly directed to readers who do not have strong training or backgrounds in science, with the intent of helping them grasp the underpinnings of this important issue. I'm going to present an ongoing series of posts that will develop various aspects of the science of global warming, its causes and possible methods for minimizing its advance and overcoming at least partially its detrimental effects.

Each post will begin with a capsule summary. It will then proceed with captioned sections to amplify and justify the statements and conclusions of the summary. I'll present images and tables where helpful to develop a point, since "a picture is worth a thousand words".

Showing posts with label wildfires. Show all posts
Showing posts with label wildfires. Show all posts

Thursday, January 24, 2019

Former Vice President Biden Says Climate Change Is An “Existential” Threat

Former U. S. Vice President Joe Biden spoke before the United States Conference of Mayors on January 24, 2019.  Following the link above takes you to the YouTube video of his address.  Fully half of his 30-minute speech was devoted to the dire need for the U. S. to address climate change rather than retreat from the issue the way the present Trump administration is doing. 

Vice President Biden summarized the important climate and economic benefits generated by the funds in the Obama administration’s Recovery Act of 2009 (intended to stimulate the economy out of the Great Recession) that were directed to mitigating climate change in the U. S.  He then proceeded to offer a heartfelt, sincere and cogent statement on why and how U. S. federal policy should continue to combat climate change by doubling down on policies that reduce greenhouse gas emissions and build a renewable energy economy.  By doing so the U. S. would rejoin all the other nations of the world in our unified campaign to limit further global warming, to which we all subscribed in the Paris Agreement of 2015.

The link above takes one to the video of Biden’s speech.  The portion dealing with climate change begins at about 16 min, 19 sec (16:19) of the video, and continues to about 29 min, near the end.  (For those unfamiliar with YouTube, if you mouse over any part of the video screen the timeline of the video pops up at the bottom of the screen.  Then as the mouse scans along that timeline, you can stop at 16:19 [or any other time you wish].  If you then click on that position the video will begin playing at that point.)

Here are some direct quotes from Biden’s talk, with the time for each statement indicated.

  • The Recovery Act included “the single biggest investment in clean energy in the history of the country - $90 billion.  It leveraged $150 billion in the private sector. [It] created hundreds of thousands of clean energy jobs…By the end of the administration there was 30 times as much solar energy and [we were] creating clean energy jobs 12 times faster than any other sector of the economy.” (16:19)
  • “There’s no reason that in 2025 all of North America can’t get half of electricity from non-polluting sources.  It’s within our grasp but for special interests!” (20:40)
  • Addressing the mayors directly, he said “You also know…it’s a matter of survival.  The threat posed by climate change is existential.” (21:26)
  • “You know what the military said [to President Obama and Vice President Biden]?  ‘You know what our greatest security threat is?  Global warming….If sea levels rise…you have tens of millions of people migrating.  That’s how wars start.’” (21:42)
  • “Our government’s own most recent report found that heat stress and drought can kill up to a quarter of our corn and soybean harvest.  What’s that going to mean for you mayors from the Midwest…? What does that mean … when John Deere [a major manufacturer of farm equipment] has nothing to plow? (23:40)
  • Our scientists have spoken…Since when did we become science deniers?  The United Nations told us…we have 12 years to act before it’s irreversible” (24:07)
  • (Referring to the Trump administration intention to pull out of the Paris Agreement)…“you’ve stepped up [addressing the mayors]….400 of you said, no, no, not me….57% of you pledged to take action in 2019”  (25:50)
  • “…this is the most urgent priority facing the nation, and we’ll be judged by our children and grandchildren for what we do today.” (27:48)    

  Conclusion

This writer finds it highly significant that Vice President Biden, in his appearance before the United States Conference of Mayors for 2019 devoted so much emphasis to the single issue of climate change.  With all the problems facing our mayors, such as economic and social injustice, and opioid abuse, to name only a few, he chose to stress the importance of the climate change issue as an “existential” threat, stating “this is the most urgent priority facing the nation”.

Skeptics may downplay this speech as being merely a political gesture from someone grappling with the decision of whether to run for president in two years.  Yet there are many other ways he could have addressed our country’s mayors.  Here’s a man who was at the center of national power for eight years.  He came to understand the singular, generational, global significance of man-made emissions of greenhouse gases that have led to intolerable levels of global warming in the short time, geologically speaking, of a figurative blink of an eye.  Mr. Biden is to be praised for this effort.  We all should support his call to action on climate change, regardless of whether he runs for president.

© 2019 Henry Auer

Friday, November 17, 2017

Role of Global Warming in Present and Future Hurricanes

Summary.  The day that Hurricane Harvey made landfall in Texas the water temperature in the Gulf of Mexico was about 3-7°F higher than the average for 1961-1990.  This is important, because warmer water releases more moisture into the air than cooler water, feeding heavier rainfall.  This contributed to the extreme, unprecedented flooding in the Houston area caused by Harvey.  More moisture also leads to stronger winds in storms.
Climate models project that if humanity continues to burn fossil fuels without restraint the added carbon dioxide produced will lead to sharply higher global average temperatures.  These will produce more frequent and intense extreme weather and climate events, which bring serious socioeconomic harms to society.  One model study of storm activity along the Texas coast finds that the probability of an event will triple, from 6% per year to 18% per year, by the end of this century if emissions continue unabated.

Climate scientists have been warning of major climate consequences from man-made greenhouse gas emissions for almost three decades.  Those predictions have not changed, indeed have only improved, as scientific capabilities grew.  If humanity had responded earlier, the costs of action would have been lower or spread over longer times.  In the absence of past action at the scale needed, now is the time to act.
 

Introduction.  Climate scientists understand that the long-term global average temperature will continue to increase largely in response to the increased concentration of carbon dioxide (CO2) and other greenhouse gases (GHGs) in the atmosphere.  CO2 is increasing since it is the combustion product of humanity’s burning of fossil fuels (i.e., fuels based on carbon: coal, petroleum products and natural gas).  Other GHGs likewise arise from human activity.  CO2 is especially significant since, once emitted into the air, it resides there for centuries; it continues accumulating without balancing effects that remove it from the atmosphere (after about one-third of it dissolves into the ocean).
The greenhouse effect originating from these excess GHGs raises the global average temperature.  The temperature will remain elevated in coming centuries as the excess GHGs continue residing in the atmosphere. 
One effect of higher temperatures at the surface of lakes and oceans is that more water evaporates as the water temperature rises, by about 4% per degree F (about 7% per degree C).  In addition, evaporation of water vapor requires the input of heat; as a result the surrounding air momentarily cools off.  Conversely, as water vapor condenses, such as in cloud and raindrop formation, heat is released, warming the surrounding air momentarily.  These temperature changes lead to local winds. 
Storms such as hurricanes sweep over ocean water and entrap large amounts of water vapor.  When the vapor condenses the liquid falls to the ground as rain.  As this activity intensifies strong winds result.  Climate scientists foresee that as the earth warms, storms such as hurricanes will potentially carry more water vapor and generate stronger winds than in earlier decades.

Continued GHG emissions will lead to a higher incidence of extreme hurricanes.

The United Nations-sponsored Intergovernmental Panel on Climate Change (IPCC) pubished its Fifth Assessment Report, Part 1, in 2013.  It includes climate model projections of the relationship between the excess CO2 accumulated in the atmosphere from human activity and the predicted increase in the global average temperature resulting from the added CO2. 
The models were run by assuming four CO2 emission scenarios up to the year 2100: the most stringent ends GHG emissions beyond 2050, while the least stringent continues current use and unabated future growth in use of fossil fuels.  The results are shown in the graphic below, showing the dependence of the global average temperature on the atmospheric CO2 level, including the historical record of global average temperature from 1880 to 2010 in the lower left of the image.
 
Historical record of global annual temperature increase above the average for 1861-1880 (vertical axis) as a function of historical atmospheric accumulated weight of excess carbon dioxide, due to human use of fossil fuels, above the level in 1870 (black; lower left).  The circles mark decades from 1870 to 2100.  Future model projections of the same temperature-carbon dioxide dependencies are shown from 2010 to 2100, based on four scenarios describing the stringency of policy used to limit future emissions (dark blue, most stringent; light blue, next less stringent; orange, weak limits on emissions; red, continued emissions from unabated use of fossil fuels).
Source: Intergovernmental Panel on Climate Change, Fifth Assessment Report, Working Group 1, Summary for Policymakers. http://www.climatechange2013.org/images/report/WG1AR5_SPM_FINAL.pdf .


The historical data show that in 2010 the global average temperature was about 0.9°C (1.6°F) higher than in 1870.  The modeling shows that the most stringent scenario (dark blue) projects a temperature increase above the 1870 level of about 1.8°C (3.2°F) by 2050-2100.  On the other hand, the scenario based on unconstrained continued use of carbon-containing fuels (red) foresees that the global average temperature in 2100 will be about 4.7°C (8.5°F) above the 1870 temperature.  Such a drastic increase in global temperature will lead to periods of time, and/or regions of the earth’s surface, experiencing one or more of fierce heat waves; extreme storms that may be more frequent, or have more intense rainfall and winds; droughts; wildfires; and pronounced increases in sea levels.
Hurricane Harvey pummeled Houston and neighboring regions with torrential rainfall in August 2017.  While the hurricane would likely have happened anyway, rainfall was more intense because the water of the Gulf of Mexico was warmer than in the past.  This is seen in heat map for the Gulf, shown below for the day that Harvey made landfall.
               Source: http://www.climatesignals.org/node/7158 (accessed late August 2017).

 
(The legend under the heat map is the one appearing on the web site from which the map was copied.)  The map makes clear that the excess heat in the Gulf of Mexico abutting the Texas coast, shown by the color code bar at the right, was a factor in the extreme rainfall and flooding generated by the storm. As explained in the Introduction, warmer water leads to more moisture evaporating into the storm.   A second factor was that the hurricane lingered over the Houston area for several days.  The total rainfall from the storm at Cedar Bayou was 51.88 in (1318 mm), perhaps the highest in the region.

The likelihood of a return event of a hurricane like Harvey increases 3-fold in the unrestrained emission scenario described above for the first graphic.  K. Emanuel published an analysis analysis of hurricane rainfall properties by modeling previous storms impacting Texas.  This was carried out historically for the period 1980-2016, and with the unrestrained scenario for 2081-2100.  He developed results assuming a storm with 500 mm (19.7 in) of rainfall, much less than the local maximum cited above for Cedar Bayou.  The likelihood of such precipitation is evaluated at 6% per year for 2017, and increases three-fold to 18% per year by the final decades of this century if fossil fuel use remains unconstrained. Emanuel also found that for the period 1981-2000 the historical likelihood is modeled as 1% per year.  Thus, his modeling shows that global warming has already increased hurricane/storm likelihoods in recent decades by a factor of six, and for the century-long interval from the end of the 20th century to the end of 21st century by 18-fold. 

Conclusion

Climate scientists have been warning for almost three decades of the hazards arising from increased levels of greenhouse gases in the atmosphere.  The increase in atmospheric CO2 from 1958 to the present is shown below.

Atmospheric concentration of CO2 in parts of CO2 per million parts of air; ppm).
Source: www.CO2.earth.
 
From the first IPCC Assessment Report in 1990 to the fifth in 2013-2014, the forecasts of future climate trends and harmful events have not changed.  It was already understood in1990 that manmade global warming imperiled our society’s wellbeing.  What has changed is first, an increase in the CO2 level from about 355 ppm in 1990 to 402 ppm in August 2016 (see the graphic just above); and second, increased certainty in the predictions of the effects of higher levels of greenhouse gases on the earth’s climate, arising from dramatic increases in data available, sophistication of climate models employed, and the computational power of modern supercomputers.
The flooding from the hurricanes that struck the Caribbean and southeastern U. S. in the summer of 2017 is just one example of the types of extreme events that climate scientists have foreseen over the past decades.  Others include heat waves, droughts, forest wildfires and sea level rise.  In the earlier decades they were only predictions, dismissed by many.  But by today the warnings have come to pass; extreme events will increase in occurrence and severity as warming worsens.
The harms and damages inflicted by extreme events have major economic and societal consequences.  The need arises to reconstruct damaged homes and facilities and to undertake projects that increase resiliency in the face of future climate threats.  These costs ultimately fall on the population at large, for example from increased insurance premiums and higher taxes.  Had earlier action been undertaken it is likely that such societal costs would have been lower, or at least spread out over longer time frames. 
As of today, however, much of the response is on an emergency basis, i.e. as the response to unforeseen disasters.  The U.S. in particular, as well as the world at large, should accept the reality of the climate change threat.  We must make the investments now that are needed to minimize further greenhouse gas emissions and to adapt to the threats already with us.

© 2017 Henry Auer


Friday, April 7, 2017

The Centennial Celebration of the Paris Agreement Arrives 99 Years Early

Early in 2016, shortly after the United Nations-sponsored meeting that culminated in the Paris Climate Agreement of 2015, this writer posted a fable characterizing a fictional centennial commemoration of the 2015 Agreement in a scenario in which use of fossil fuels had continued unabated during that 100-year interval.  The fable is reproduced below:

The Centennial Commemoration of the 2015 Paris Climate Agreement

A Fable

It was December 2115, the hundredth anniversary of the agreement to a climate treaty reached among all the members of the United Nations, in Paris.  The members of the Petrex extended family gathered to mark the occasion.  By that time, three to four generations after the event, the clan had grown considerably, and had established for itself a fully self-sufficient environment inside its terradome.  For the occasion the space was opulently fitted out with an artificial lake in which were moored several model oil rigs.  The pipe linking the rigs to shore ended in an internally illuminated fountain gurgling champagne.  Scattered about the artificially-turfed land areas were several working model oil wells erected in mud fields of black caviar, pumping dark chocolate and coffee liqueurs, and other reminders of the black gold that had started the Petrex fortune, more than one hundred years earlier.

Back then, the clan founder, Malvolio Petrex, chairman and chief executive officer of the largest oil company at the time, had come to realize the inconsistencies of his, and his company’s, position.  They were, at one and the same time, using all their financial power and political influence to perpetuate, indeed to expand, the use of the oil they extracted from the ground, while correctly realizing that their exploitative activities were worsening the global warming already well under way.  After all, the Paris agreement itself was reached in response to expert scientific findings, reported for at least the preceding twenty years, that burning oil and other fossil fuels, such as those his company and others were pulling from the ground, added irreversibly to the atmospheric burden of carbon dioxide, a powerful greenhouse gas.

Malvolio Petrex knew that global warming was going to get much worse in the coming years, because his company and others were continuing to produce fossil fuels at ever-increasing rates of growth, year after year.  After all, more and more energy was needed to fuel the demands of economies all over the world, being used to expand their economies and raise the poorest peoples of the world out of poverty. 

He wasn’t too worried about his own welfare, though.  Thanks to his immeasurable wealth, he already had peppered several secure estates around the world, in various climatic and ecological settings.  But as any other dynastic figure that we may encounter throughout history, he was concerned about the wellbeing of his progeny.  He knew that the travesties his business activities were creating would worsen after he was gone, impacting the lives and indeed the safety of his scions.  He understood that worsening warming would lead to economic and political unrest among the impoverished and others less well off than he because they would be suffering the harmful effects of warming: flooding in some regions; droughts, wildfires and famine in others; and inexorable sea level rise driving millions around the world from their traditional homes and livelihoods.

And so he embarked on a program to develop self-contained environments for himself and his family.  The environments would insulate his family from the unpleasantness of dealing with the effects of climate change by keeping the open atmosphere out, and the family’s living quarters and areas for amusing themselves in.  The first models were installed on the grounds of his existing estates, and were relatively modest. 

Now, one hundred years later, after many rounds of development and improvement, this Petrex estate was enveloped in its own protective terradome.  It was a large, fully enclosed environment covering almost one square mile, incorporating the estate’s mansion, its recreational areas, and fields producing much of its food needs.  The terradome insulated the estate from the worst “weird” climate and weather events brought on by the extreme warming that the world had attained by then, as well as keeping a portion of the sun’s warming light from penetrating to the land within it.  The Petrex family had practically no need to travel outside the terradome; it was almost entirely self-sufficient.

As a result, they were insulated as well from the harms and damages induced by the warmer climate that most of the peoples of the world were suffering.  Or maybe they knew and, just like Malvolio Petrex a hundred years earlier, chose to ignore it.  The population at large was subjected to far worse conditions than Petrex’s world had experienced one hundred years earlier: debilitating heat waves and droughts, intense storms bringing on severe flooding, encroaching oceans because of the severe degree of sea level rise, all brought on by the excess global warming that burning fossil fuels induced. 

By the time of the centennial anniversary the opportunity for effective action to combat global warming had long passed.

 
                                          *         *         *        


The fabled centennial celebration of the Paris Agreement has already arrived, 99 years early.  The newly elected U. S. President, Donald Trump, is a man whose wealth could well serve as a model for the patriarch Malvolio Petrex.  He shows his wealth at least partly by erecting palatial residences and developing exclusive golf courses around the globe. 

Mr. Trump has called global warming a hoax.  Now as president he is implementing policies and appointing people to important cabinet positions who share his sentiment.  From the outset, he is reversing important initiatives undertaken by his predecessor, who had set in motion important policies that curb emissions of greenhouse gases.   

Here is a partial list of President Trump’s actions and policy positions:

·        He appointed Scott Pruitt to be Administrator of the Environmental Protection Agency (EPA). Instead of having an interest in protecting the environment, Mr. Pruitt is eliminating rules that preserve our natural world.  In his previous position as the Attorney General of Oklahoma, he repeatedly sued the EPA seeking to overturn its regulations that protect aspects of our environment, including emissions of greenhouse gases. Now he is the Administrator of that selfsame agency.  The Los Angeles Times writes “The Republican dogma of unrestrained economic exploitation drives the president and his EPA chief. As a result, climate science has become a heretical activity.”

·        Among fossil fuels coal emits the most carbon dioxide (per amount of heat obtained) when burned.  So its use should be limited as much as possible in order to reduce emissions.  But Secretary of the Interior Ryan Zinke ordered that a ban on mining coal on federal lands, put in place by former President Obama, be rescinded.  The order followed through on President Trump’s overall goal of increasing American energy independence.

·        PresidentTrump ordered a review of all policies deemed to interfere with enhancing America’s energy independence.  This includes directing Administrator Pruitt to reconsider the Clean Power Plan, an EPA regulation issued under President Obama that would produce significant reductions in carbon dioxide emissions from the electric power industry.

·        President Trump issued an order to review the program, issued by EPA and the Department of Transportation under President Obama, significantly increasing automobile Corporate Average Fuel Economy (CAFE) standards by 2025.  The review may lead to weakening the requirements or slowing the timeline for the CAFE regulation.

·        The budget proposal that President Trump outlined for Fiscal Year 2018 seriously cuts scientific research in many agencies of the U.S. government.  Concerning  activities related to curbing global warming, the proposal completely eliminates the Department of Energy’s Advance Research Projects Agency-Energy unit, reduces research support for the National Oceanographic and Atmospheric Administration by 52%, and cuts EPA research by 48% and National Aeronautics and Space Administration earth science research by 6%.  These agencies engage in essential research on the state of the planet’s climate and provide seed or venture funding for development of new technologies that lower greenhouse gas emissions.

President Trump, could easily serve as a model for Malvolio Petrex, since he can insulate himself from the ravages of intensified global warming.  His policies, to be implemented 99 years before the centennial of the Paris Climate Agreement, will have major immediate effects and indirect ramifications that worsen greenhouse gas emissions and lead to more severe harmful consequences of warming.  Yet we may imagine that, with the vast resources he controls, his children, grandchildren and further progeny can create environments for themselves that will protect them from harms and damages that global warming brings.  The same can be said for those he selected to implement his policies. 

But the peoples of the earth, considered at large, are not so lucky.  They can’t easily shield themselves from climatic harm.  They could well be defenseless victims of President Trump’s policies.  The climate framework that Mr. Trump is overthrowing, begun under President Obama and implemented worldwide with his leadership, could make significant progress to minimizing those risks. 

It’s not too late for the Trump Administration to reconsider, and rejoin the compact of the world’s nations to lower greenhouse gas emissions. 

      © 2017 Henry Auer

Thursday, March 17, 2016

Attribution of Extreme Events to Global Warming


The public, when contemplating global warming, includes those who question whether warming underlies the occurrence of extreme weather and climate events.  The U.S. National Academies of Science, Engineering and Medicine recently issued a report, “Attribution of Extreme Weather Events in the Context of Climate Change”.  It emphasizes that the appropriate format for questions concerning this issue can be phrased in terms such as “Are events of this severity becoming more or less likely because of climate change?” 

The report emphasizes that because of rapid advances in data analysis and climate modeling the severity of many extreme events can be attributed to contributing factors arising from warming.  It includes a schematic image, shown here, characterizing how the increasing degree of understanding of various types of events leads to increasing confidence in the degree to which we can attribute severity to contributions from global warming.

This post concludes with a selection of examples from the climate literature where such analyses have been made, leading to affirmative statements of attribution such as considered here.


Recently weather news has reported on extreme events in many regions of the world. 

  • The American states of Texas and Louisiana, and their neighbors, had intense rain for over a week in early 2016, triggering record-breaking flooding in the area.    
  • The American West has suffered severe drought conditions for four years, straining water supplies and lowering yields of important crops. 
  • Perth, Australia had a heat wave four days long with temperatures over 40ºC (104ºF) in February 2016, and has had seven days over this temperature this season.  
  • Pakistan has had increasing numbers of serious flooding events over the last century, including 40 events in the last 15 years.  Most of these are accompanied by loss of life and social dislocation, and significant damage to structures and agricultural lands.
These few anecdotes are potentially significant indicators of the effect that global warming is having at regional and local levels around the world.  Indeed, increased rates of occurrence of such phenomena are predicted with high confidence in recent global warming reports.  But in discussing the role of warming at the scale of such geographically small areas it is important to evaluate whether each one in fact is related to warming.  For example, if few or none are, climate science would be hard pressed to persuade policymakers and the public to undertake efforts to minimize further warming and adapt to its effects.  On the other hand, if it can be shown that there is indeed a contribution from warming, then climate science is justified in actively pursuing appropriate policies such as those agreed to at the United Nations conference in Paris in December 2015.

Here we discuss the question of whether, and how, extreme events can be attributed to global warming.

The U. S. National Academies of Sciences, Engineering, and Medicine issued the report “Attribution of Extreme Weather Events in the Context of Climate Change” (2016); Washington, DC: The National Academies Press (the Report) on March 10, 2016.  The Report emphasizes that extreme events, just as all our weather every day, results from the interactions of many atmospheric forces and processes.  For this reason, it makes the very important point that we can not justifiably ask a question such as “Was this extreme event caused by [man-made] climate change, yes or no?”  Such a simplified black-or-white question overlooks the complexity in climate and weather. 

Rather the Report offers different questions phrased as “Are events of this severity becoming more or less likely because of climate change?”; or, for single events such as local storms, the question could be “To what extent was the storm intensified, or its precipitation increased, because of climate change?”  Note that the questions deemed appropriate seek expressions of likelihood, rather than the certainty demanded by the yes-or-no question.  To any viewer of a televised weather forecast this should hardly be surprising.  After all, these daily predictions always provide likelihoods for sunshine (clear, partly cloudy, mostly cloudy, etc.) as well as percent probabilities of rain, sleet or snow.  In the same way, and for the same reasons, the Report concludes that statements of attribution should be phrased in terms of the probability or likelihood that global warming was a climatic factor contributing to the occurrence of the extreme event.

The Report summarizes its detailed deliberations about attribution of events to known or understandable contributing factors with a simplified conceptual diagram, shown here
 
Schematic diagram showing how our confidence (vertical axis) in attributing different kinds of extreme events to man-made climate change depends on our understanding of the extent to which climate change affects the particular type of event (horizontal axis).  Different types of extreme events are shown by the differently colored labeled circles.  The dashed line represents where a particular type of extreme event would fall if we had an ideal ability to attribute how climate change affects it.  In reality all the circles fall below the dashed line because our ability to attribute the specific events to man-made climate change is less than perfect.  Note that the understanding/attribution level is high for temperature events (upper right), and that these become lower as we pass through extreme rainfall (near the center) to severe convective storms (e.g., thunderstorms and tornadoes; lower left).
Source: U. S. National Academies of Sciences, Engineering, and Medicine,  “Attribution of Extreme Weather Events in the Context of Climate Change” (2016); Washington, DC: The National Academies Press. doi: 10.17226/21852.
 
 
The Report identifies two ways to label an event as “extreme”.  We have to be able to distinguish a supposed extreme event, potentially caused in part by the effects of global warming, from normal behavior.  First, data characterizing the event could be shown to differ from comparable data for a reference period extending over a sufficiently long period of time, with a high level of statistical significance.  Alternatively, data characterizing the event could be successfully modeled in a climate model that includes man-made global warming factors, whereas it could not be modeled by a similar model run excluding those factors, again, with a high level of statistical significance.  An event that fulfils either of these conditions can then be labeled as an event to which global warming contributes to its extreme character.
 
Extreme events had already been attributed to global warming before this Report. 
 
  • Analysis of data over the 49 year period from 1951-1999 shows that global warming is responsible for extremes of rainfall over the Northern Hemisphere.  Min and coworkers (Nature, 2011, Vol. 470, pp. 378-381, doi:10.1038/nature09763) showed that “human-induced increases in greenhouse gases have contributed to the observed intensification of heavy precipitation events found over approximately two-thirds of … Northern Hemisphere land areas.”  This work is significant because it covers a period of time in which greenhouse gas levels, and global average temperatures, were much lower than at present.
 
  • Extreme rainfall and catastrophic flooding in England and Wales in 2000 was very likely due to human-induced global warming.  Pall and coworkers carried out a probabilistic analysis of weather patterns and likelihood of flooding in the region (Nature, 2011, Vol. 470, pp. 382-385, doi:10.1038/nature09762). During October and November 2000 England and Wales had the heaviest rainfall since records began in 1766, leading to severe flooding. The authors concluded “it is very likely that global [human-induced] greenhouse gas emissions [occurring during the twentieth century] substantially increased the risk of flood occurrence…in autumn 2000.”
 
  • Kelley and coworkers (Proc. Natl Acad. Sci., published online before print March 2, 2015) report on the worst drought in recorded history in Syria and neighboring countries just prior to the “Arab Spring”.  The drought was serious enough that large numbers of farmers left their villages and migrated to Syria’s cities.  This caused major social and political turmoil and is considered to be a contributing factor to Syria’s ongoing civil war.  The authors found that human-derived greenhouse gases contributed to the drought.
 
  • Moore and Lobell (Proc. Natl. Acad. Sci., vol. 112 no. 9, pp. 2670–2675, 2015) analyzed changes in crop yields and climate change across Europe between 1989 and 2009.  Large scale decreases in yields were found in many localized regions, which correlated with increased temperatures and decreased precipitation over the 20 year period studied.
 
  • Diffenbaugh and coworkers (Proc. Natl. Acad. Sci., published online before print March 2, 2015) examined the drought in California from December 2012 to September 2014, likely the worst in 1000 years.  By simulating the region’s climate in model calculations the authors found that the extra amount of greenhouse gases added by human activity likely resulted in higher temperatures and reduced precipitation in the region.  This factor also contributes to a high risk of continued severe droughts.
 
  • Williams and coworkers also conducted detailed analyses of climate-related data for California, from 1901 to 2014 (Geophys. Res. Let. 2015; DOI: 10.1002/2015GL064924).  From rigorous statistical analysis the authors estimated that global warming was responsible for 8-27% of the observed excess drought conditions for 2012-2014, and for 5-18% for 2014 alone.  These findings indicate that although drought conditions may originate from various climatic factors operating cyclically over many years, its full extreme extent in the current drought has been worsened by global warming, producing the current record conditions.
 
  • Cook and coworkers (Sci. Adv. 1, e1400082 (2015); published electronically 12 February 2015) assessed drought conditions in the American Southwest and Central Plains.  Assuming that unrestrained emission of greenhouse gases would continue, the risk of severe droughts in these regions is projected to be extremely high, by various measures between about 69% and 97% in the second half of this century.
 
Conclusion
 
The Report by the National Academies makes clear that climate science has advanced remarkably in the last decade, so that attributions of global warming as a contributing factor to extreme events can reliably be made after appropriate analysis.  This depends on use of one or both of the methods, either data based or model based, mentioned above.  The progress making this possible includes the availability of far more observational data, on the one hand, and constant improvements in climate models on the other.  As a result statements of attribution, when merited based on analysis, now authoritatively support the role of man-made global warming, due to humanity’s continued and increasing use of fossil fuels, in the increasing severity of various types of extreme climate and weather events.  We all, as citizens of countries around the world, must marshal our efforts to reduce emissions as aggressively as possible.  The goal should be achieving near zero annual emission rates within a few decades, say by mid-century.
 
© 2016 Henry Auer

Friday, March 4, 2016

The Centennial Commemoration of the 2015 Paris Climate Agreement. II.

A Fable

Paris is sparing no extravagance for the centennial celebration of the 2015 climate agreement, themed “Paris 2115”.  The Eiffel Tower is decked out with the newest efficient lighting fixtures, highlighting the sky blue of the United Nations flag, intermingled with the Tricouleur, the red, white and blue of the French flag.  Laser light shows projecting these colors playfully pierce the air around its spire.

The Étoile and Arc de Triomphe are adorned with exotic vegetation brought from far reaches of the planet, symbols of the preservation of the environment resulting from one hundred years of sustainable climate policies resulting from the agreement.

The most striking aspect of the celebration is that several hundred thousand people from all around the world have descended on The City of Light, to mark the centennial of the United Nations Framework Convention on Climate Change (UNFCCC) agreement limiting emissions of greenhouse gases.  The 2015 agreement enshrined the goal of keeping the increase in global average temperature to under 2ºC (3.6ºF) above the preindustrial temperature, i.e., the temperature before humans began burning fossil fuels.  The agreement also included the more stringent goal of keeping the rise below 1.5ºC as a more ambitious option. 

Just under 200 nations, all the U.N.’s members, joined the agreement.  Now the member nations are celebrating, for they had in fact summoned their resources and achieved the more stringent goal.  This required that restraint and discipline be applied by each nation, each independently of, but in concert with, the constraints developed by every other nation.  The 2015 agreement made these constraints voluntary, nation by nation.  It is remarkable that the member nations all accepted the responsibility of fulfilling their pledges, with records and validation open for all to see.  Indeed, since the original 2015 pledges were deemed inadequate to attain this goal, the nations repeatedly reconvened every five years, and intensified their efforts by developing ever more stringent reduction pledges.  The centennial we are now celebrating honors these pledge extensions.  Without these extra efforts we could not have kept the global temperature from increasing as little as it has today.

How did this come about?  After all, the energy needed for industrialization and raising living standards in developing countries, obtained almost entirely from burning fossil fuels, had underpinned their headlong rush to economic growth for more than a century.  The fossil fuel industry was a significant fraction of the world economy, and the fuel companies exerted their considerable political power to maintain the status quo, extracting ever more fossil fuels each year.  This path, called “business-as-usual”, would have brought the world to an average temperature rise of about 4ºC, a truly devastating result.

Governments the world over, working in collaboration with the fossil fuel companies and other segments of the economy, transformed the world’s energy sector.  Governments and company managements, realizing the dangers of continuing along a business-as-usual path, transformed their political frameworks and business models.  The companies came to realize that there was profit to be gained by developing and deploying renewable energy sources, and redirected their development budgets accordingly.  New research and great economies of scale made solar and wind energy, for example, economical yet highly profitable.  Energy storage was optimized with new battery compositions and physical storage modes.  People began to see new beauty in renewable energy installations.  In the meanwhile, biotechnology researchers developed genetically modified crop plants that withstand the stresses of heat and drought more effectively than the old wild strains.  Research ingenuity also optimized yields of biofuels to provide all the needs of the growing airline industry.

Our land transportation has also been revolutionized.  Self-driving vehicles now navigate e-highways, minimizing the need for extra weight to protect us from crashes.  They are powered by newly developed highly efficient renewable energy sources.

Sadly, several small island nations that signed on to the agreement in 2015 no longer exist, because their islands were swallowed up by rising seas over the intervening one hundred years.  Already by 2015 sea level had been rising because, averaged over the seasons of the year, more ice melted from polar ice masses into the ocean than was deposited by fresh snow and ice.  Rising seas were already locked in by then.  Indeed, by 2015 ice loss had been accelerating because temperatures over the ice masses were rising rapidly.  Now as we fete the centennial, many coastal regions around the world have been lost to ocean inundation.

Pingali, Richard and Hailong met each other last night at the Korean pavilion.  Paris 2115 is organized around these centers, representing each nation of the UNFCCC agreement, all around the city.  Each one displays highlights of the environmental and sustainability contributions they have made in the past hundred years that brought us to this week’s celebration.  The three new friends are circulating among the pavilions, trying to take in as many as they can, from countries large and small. 

The celebration reaches its peak tomorrow, as major personalities from the UNFCCC and various nations speak about the significance of this occasion, and the way forward.  Of course these speeches will be streamed live as holographic displays in all the pavilions, so that all the celebrants can experience the immediacy of the presentations.
 

                                      *        *        *        *

 
The Paris Agreement reached in December 2015 represents major progress on the path to controlling worldwide emissions of greenhouse gases.  All 197 U. N. member nations agreed to its terms.  This accomplishment is due in large part to departure from earlier attempts at negotiating a treaty involving imposing predetermined limits on emissions from each nation.  Instead the Paris Agreement solicits voluntary pledges from each which, once filed, are subject to review and verification by the U. N. 

Prior to the convening of the Paris meeting almost all nations had already submitted their pledges.  A scientific evaluation shows that those pledges are insufficiently ambitious to achieve the goal of keeping the global average temperature increase less than 2ºC during this century.  Climate model calculations by  Fawcett and coworkers (Science, 2015, Vol. 350, pp. 1168-1169) show that the current voluntary pledges will keep the annual

 

Actual (up to 2010) and projected annual rates of emission of CO2 from energy and major industrial sources from 1990 to 2100.  The heavy lines are summary representations for four emissions scenarios.  Top to bottom these are the reference case of no emissions reduction policy in place; no reduction policy up to 2030, then a 2% per year reduction in emissions; implementation of only the current voluntary pledges through 2030, continued unchanged to 2100 (curve labeled INDCs); and the current voluntary pledges to 2030, then further reduction by at least 5% per year to 2100.  The individual thin lines are actual modeling runs repeated many times.  IPCC, Intergovernmental Panel on Climate Change; AR5, Fifth Assessment Report issued 2013-4.
Source: Fawcett and coworkers, Science, 2015, Vol. 350, pp. 1168-1169; http://science.sciencemag.org/content/sci/350/6265/1168.full.pdf .

 

rate of CO2 emissions level at their present rates up to 2100 (curve labeled INDCs in the graphic above).  Since these are annual rates, the emissions will continue to raise the total accumulated CO2 level throughout this period, leading to a steady rise in global average temperature to 2100.  Only the lowest heavy blue curve shows a decreased rate of annual emissions after 2030, accomplished in the model by imposing a stringent reduction in annual emissions rate of 5% per year.  The accumulation of CO2 in the atmosphere continues, admittedly at lower rates, throughout this period.  As a result the global average temperature will still continue rising from its present (unprecedented high) value at a slow but measurable pace.

The Paris negotiators recognized this deficiency, and included the intention in the Agreement to reconvene in five years to assess progress and to encourage updated pledges including more ambitious emission reductions from the member nations.  It also mentions explicitly the more stringent goal that reductions should in fact be ambitious enough to keep the increase in global average temperature below 1.5ºC.

Some nations and provinces around the world have already undertaken efforts to lower greenhouse gas emissions. China’s pledge lays out increasing annual emissions until 2030, mainly from burning coal, then a reduction in that rate.  But the recent economic slowdown in that country appears already to be leading to lower emissions than anticipated.  As part of its pledge, China intends to expand pilot cap-and-trade limits on emissions in some of its cities to the nation as a whole.

Australia imposed a carbon pricing scheme in 2012, but it was repealed in 2014.  In addition Australia is now severely cutting back its spending on its respected government scientific research organization, including its climate science section.  This impedes the country’s and the world’s ability to track its greenhouse gases and temperatures.

The European Commission announced a plan in 2010 to reduce emissions by 80% below 1990 levels by 2050.  Europe implemented a cap-and-trade Emissions Trading Scheme (ETS) a decade ago as part of its participation in the Kyoto Protocol, the UNFCCC agreement preceding the Paris Agreement.  The ETS has had difficulties that are preventing it from achieving its full potential.

The U.S. federal government has been unable to enact laws to limit emissions because the majority party in one or both of the Congress’s chambers does not admit the need to address man-made global warming.  But President Obama has undertaken executive steps that will double fuel efficiency of the nation’s vehicles, and will increase the efficiency of electricity generation in electricity generation.  Independently, California and some other states have policies limiting emissions similar to the reduction intended by the European Commission.

In Canada, the province of British Columbia has had a revenue-neutral carbon tax in place since 2008.  Revenues collected from the tax are used to lower tax rates in other categories.  Use of fossil fuels has dropped with no effect on the province’s economy.

 
Conclusion

 
Implementation of the Paris Agreement of 2015 promises to turn our world from a warming disaster to a manageable, but palpably warmer, global environment.  But there are powerful political and commercial interests opposing the changes needed to stabilize the global climate.  Business models of large multinational energy companies need to change, such that they recognize that profits can be derived from producing renewable energy.  Deep-rooted psychological barriers also exist that resist our need to change our ways.  With good will and ambitious planning the fable represented by Paris 2115 may come to pass.
 
© 2015 Henry Auer