Friday, October 24, 2014
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Climate Change by the Numbers

LONDON – Governments around the world have just received one of the most important scientific reports ever written. It provides the starkest assessment yet of how the earth’s climate is responding to rising levels of greenhouse gases in the atmosphere and creating risks for billions of people from extreme weather events and rising sea levels.

A confidential draft of the new report on the causes and consequences of global warming was sent to governments to review on June 7, ahead of the publication of the final version this autumn. Compiled for the Intergovernmental Panel on Climate Change by 255 scientific experts from universities and research institutes in 38 countries, the report provides an up-to-date overview of the findings of thousands of recent peer-reviewed research papers.

Most important, the latest IPCC report – part of its fifth comprehensive assessment in its 25-year history – includes an analysis of new computer projections of how global warming might develop by the end of the century. The initial results show that, at current rates of emissions of carbon dioxide and other greenhouse gases, average global temperature could be at least three degrees centigrade higher by the end of this century than it was before the onset of the Industrial Revolution and widespread burning of fossil fuels.

At a United Nations summit in 2010, governments agreed that emissions should be reduced sharply in order to limit global warming to two degrees centigrade by the end of this century. So the new IPCC report is likely to increase pressure on world leaders ahead of another UN meeting in 2015 to conclude a new international treaty on climate change, including legally binding emissions cuts.

Among the major issues that have been covered by recent research – and that are addressed in the IPCC report – are current trends in greenhouse-gas concentrations and global temperatures. The scientific literature indicates that the level of atmospheric CO2 today is about 40% higher than the pre-industrial level. It is at its highest since the Pliocene Epoch about three million years ago, when the planet was 2-3 degrees centigrade warmer, the polar ice caps were much smaller, and the global sea level was about 20 meters higher.

Meanwhile, global surface temperature has already risen by about 0.8 degrees centigrade. Although the rate of increase has been lower over the past 15 years than it was before, nearly all climate scientists believe that the slowdown is temporary, and that warming will accelerate again in the near future.

Governments will negotiate a summary of the new IPCC report line by line at a special meeting in Stockholm at the end of September, with the main report to be published shortly thereafter. Two more major reports – focusing on the challenges of adapting to the effects of climate change and how to mitigate the worst potential consequences through emissions cuts – will follow next year. Together with a synthesis of the main conclusions, they will complete the fifth assessment.

The IPCC, established by the World Meteorological Organization and the United Nations Environment Program, has provided policymakers with authoritative information concerning the state of knowledge about climate change since 1988. Its last comprehensive assessment, in 2007, concluded that global warming over the previous 50 years had been “unequivocal,” and that there was a 90% chance that most of it was caused by human activity, such as the burning of fossil fuels.

But the IPCC also attracted controversy when it admitted in 2010 that a volume on the consequences of climate change erroneously suggested that, at current rates of melting, all of the glaciers in the Himalayas would disappear by 2035, rather than within a few centuries.

This small but significant mistake prompted an invitation from the IPCC to the world’s leading national science academies to review its procedures.

As a result of the academies’ recommendations, the IPCC tightened its review methods, created a new process for correcting possible mistakes in future reports, and introduced a more explicit policy for dealing with potential conflicts of interest among authors.

Opponents of the IPCC have unsuccessfully attempted to undermine the new report by selectively leaking earlier versions. They have quoted sections out of context in order to create a misleading impression of its contents, falsely claiming that research shows that cosmic rays from outer space are responsible for global warming.

Nevertheless, governments and the public can be confident that the report will be the most reliable scientific assessment of climate change that has ever been produced. Most critically, it will allow people to read for themselves the authoritative verdict of the world’s scientific community on the evidence for climate change. Citizens can then judge the effectiveness of efforts to reduce greenhouse-gas emissions – and decide whether their governments are doing enough to manage the risks posed by climate change.

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  1. CommentedRonald Abate

    The IPCC reports are not to be trusted. Most of those filling reports are hand-picked by governments for their advocacy of catastrophic anthropogenic global warming (CAGW). Here are some unbiased sources of information on the hugely complex science of our chaotic climate system.

    Judith Curry hosts a great blog "Climate Etc." at judithcurry.com. Dr. Curry is head of the earth and atmospheric sciences dept at Georgia Tech. She not only covers the science but also the advocacy and the sociology and psychology of the players.

    A group of retired NASA scientists and engineers from the Apollo moon landing program have formed a study group to ferret our what is scientific fact from advocacy. They have recently issued their "assessment of the science" report which is found at their website here: www.therightclimatestuff.com/

    Meteorologist Anthony Watts hosts a world famous science blog (over 150 million hits) that contains a wealth of information on climate science. Anthony was one of the first to point out the poor quality of thermometers used to measure changes in temperature that formed an important part of global warming advocacy. Anthony's blog can be found at www.wattsupwiththat.com.

    The IPCC is not to be trusted It is an advocacy organization peopled by government appointees and funded by government. Those that do the funding get to call the tune.

  2. Portrait of Christopher T. Mahoney

    CommentedChristopher T. Mahoney

    This will be a fun experiment over the next two decades: watching Western economies starve themselves of carbon while China builds hundreds of new soft-coal power plants. Here's a tip: manufacturing, refining and processing jobs go where energy is cheapest. Or maybe the millions of unemployed workers in the West can get jobs making solar panels.

  3. CommentedMauricio Ibanez

    A law with global coverage should apply to force buildings to plant grass and trees at their top in an effort to minimize the damage done on the ground when they started the building. I imagine all skycrapers and office buildings, perhaps even houses ' roofs, showing green on the top, then this in every neighborhood, everybtown, every village, this could at least delay "global warming" and give society more time to think of other solutions for alterantive fuels. This idea has been applied vountarily by constructors on "greeen" or "environmentally firendly" buildings but more like a fashion or to fill a niche market, but if we do it as a law, then we could start seeing some slow down of global warming and perhaps Earth could find faster its new climate balance.

  4. CommentedSteve Barney

    First, let's be clear. This is the subject:

    7 Jun - 2 Aug WG I - AR5 Government Review of Final Draft SPM
    http://www.ipcc.ch/scripts/_calendar_template.php?wg=8

    That's the final draft Summary for Policymakers of the Working Group I Contribution to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change, which is being reviewed by the world's governments from June 7 - August 2, 2013.

    Here's a little more detail:

    "7 June – 2 August 2013 – Final Government Distribution
    The Final Government Distribution of the Final Draft of the Working Group I contribution of the Intergovernmental Panel on Climate Change Fifth Assessment Report Climate Change 2013: The Physical Science Basis is being held from 7 June to 2 August 2013. The purpose of the WGI AR5 Final Government Distribution is to provide IPCC member Governments with an opportunity to submit written comments on the Final Draft of the WGI AR5 Summary for Policymakers in preparation of the Twelfth Session of Working Group I."
    https://www.ipcc-wg1.unibe.ch/AR5/AR5.html

    WGI Fifth Assessment Report: Chapter Outline
    https://www.ipcc-wg1.unibe.ch/AR5/outline.html

    Just the facts.

  5. Commentedchad bircher

    If what we have done in the last 15 years has substantially slowed climate change shouldn't we keep that up?
    Oh, by the way in the last 15 years global warming hasn't merely slowed down, it has stopped.
    http://www.cru.uea.ac.uk/cru/data/temperature/

  6. CommentedRichard Black

    Mark, not so. Roy Spencer, for example, belongs to a religious group that holds as an article of faith that human activities cannot change the climate. But his work at the University of Alabama contributes majorly to the 20th/21st Century temperature record. Henrik Svensmark - there are others. But not many, by definition - because few scientists choose not to accept the evidence.

  7. CommentedMark Pitts

    The article leaves unclear (perhaps intentionally) the great degree of disagreement among scientists about
    (1) the amount of warming to be expected by 2100,
    (2) what the effects would be for a given level of warming, &
    (3) the best approach for dealing with the problem.

  8. CommentedMark Pitts

    Mike has a very good point: no one gets money to study climate change if they don't believe in climate change. There is a severe selection bias, fueled by scientists who (perhaps unawares) want to get $ from world governments to promote their careers.

  9. CommentedFrank O'Callaghan

    The jury is in on this. Climate change is a reality and much of what we are now experiencing is man made. A refusal to accept this well established, Scientifically accepted and easily observed central fact is perverse.

    The real question is what, if anything, can be done.

  10. CommentedMike Nelson

    The grandiosity of the declaration that this is one of the most important scientific reports every written immediately makes it dubious. No bona fide scientific work presents itself this way. Science is is calmly measured data and conclusions. This computer modeling is an extrapolation which reflects the inherent bias of the modeler. It is not possible in today's realm of politically funded scientific research for any impartial analysis of global warming to emerge from a government-funded research institution. Why? Because no rebutal is permitted. No alternate view is allowed to be presented. This is not science. Science is about vigorous debate and multiple working hypotheses.

      CommentedJoshua Soffer

      @Mike Nelson. Why do you assume that no debate or presentation of different working hypotheses went into this overview, which, as the author stated, represents the findings of "thousands of recent multiple peer-reviewed research papers"? Is it because the results of the process of hypothesis testing among this large group of international scientists was a consensus which differs from your opinion?

  11. CommentedAnthony Juan Bautista

    "The latest IPCC report...includes an analysis of new computer projections of how global warming might develop by the end of the century."

    The above inspires the question: How well have these computer models, to date, accurately predicted trends in global warming?

    When I hear climate scientists speak of predictive computer models, I am reminded of the macroeconomists (a much larger global "scientific" cohort) and their predictive models.

    When climate scientists can model the future with acceptable accuracy, I'll believe the predictions. The same goes for the macro econs.

      CommentedMark Pitts

      Anthony is right. The models have not been tested. They have been back-fitted to fit the data (and so of course they fit!), but that is no test.
      The models are too new, and the time periods too long, to have anything resembling a test of the models.

      CommentedMark Pitts

      Anthony is right. The models have not been tested. They have been back-fitted to fit the data (and so of course they fit!), but that is no test.
      The models are too new, and the time periods too long, to have anything resembling a test of the models.

      CommentedMark Pitts

      Anthony is right. The models have not been tested. They have been back-fitted to fit the data (and so of course they fit!), but that is no test.
      The models are too new, and the time periods too long, to have anything resembling a test of the models.

      CommentedMark Pitts

      Anthony is right. The models have not been tested. They have been back-fitted to fit the data (and so of course they fit!), but that is no test.
      The models are too new, and the time periods too long, to have anything resembling a test of the models.

      CommentedMark Pitts

      Anthony is right. The models have not been tested. They have been back-fitted to fit the data (and so of course they fit!), but that is no test.
      The models are too new, and the time periods too long, to have anything resembling a test of the models.

      CommentedAnthony Juan Bautista

      Stepan--

      That's my point! I will not consent to the predictions of climate scientists (mathematized as they are) until they demonstrate greater validity.

      The "microfoundations" of climate science are indeed scientific by reasonable standards. But if a discipline can't abstract microfoundations toward the fulfillment of predictive models, then the science is far from "settled". So, before we alter the global economy (trillions of dollars), I need a little more ; )

      CommentedStepan February

      Weather models are tested for accuracy in various ways, both by attempting to track past weather and actually predicting future weather.

      Weather is a physical system and is probably simpler to model in some fundamental way, because it is not driven by human agents, which are highly complex.

      Anyway, this is the best science we've got. What have you got that's better?

      CommentedAnthony Juan Bautista

      Josh, what good and reliable science do you know that cannot create models to predict future outcomes with reasonable validity? Actually, all true things can be accurately modeled--that's how we know they're true.

      CommentedJoshua Soffer

      The predictions of macro-economists are all over the map, reflecting numerous political divisions. The international community of climate scientists, however, are overwhelmingly united in their belief that the empirical evidence irrefutably demonstrates the reality of man-made climate change.

      CommentedJoshua Soffer

      The predictions of macro-economists are all over the map, reflecting numerous political divisions. The international community of climate scientists, however, are overwhelmingly united in their belief that the empirical evidence irrefutably demonstrates the reality of man-made climate change.

      CommentedJoshua Soffer

      The predictions of macro-economists are all over the map, reflecting numerous political divisions. The international community of climate scientists, however, are overwhelmingly united in their belief that the empirical evidence irrefutably demonstrates the reality of man-made climate change.

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