The IPCC’s New Climate Science Guide for the Perplexed Policymaker

, , director of science & policy | November 2, 2014, 11:46 am EDT
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It is remarkable how many U.S. elected officials appear to be baffled about climate change these days. Despite the long scientific consensus that emissions of heat-trapping gases from burning fossil fuels and other human activities are driving disruptive changes to Earth’s climate, “I am not a scientist” has recently become the response that some members of Congress, governors, and other politicians are now giving to questions about whether they think climate change is a problem.

If you are a confused policymaker, perhaps fearful of answering the question incorrectly, fear no longer. The world’s leading climate scientists have just created a handy guide for you. Today, the Intergovernmental Panel on Climate Change (IPCC) released its Fifth Assessment Synthesis Report’s Summary for Policymakers, distilling thousands of peer-reviewed scientific papers characterizing the latest information on climate science, impacts, and solutions into just forty pages of text and graphics. The IPCC further distilled these findings into some headlines – barebone facts that any policymaker should know.

Here are ten top-line findings:

Human influence on the climate system is clear and recent anthropogenic emissions of greenhouse gases are the highest in history. Recent climate changes have had widespread impacts on human and natural systems.

Warming of the climate system is unequivocal and since the 1950’s, many of the observed changes are unprecedented over decades to millennia. The atmosphere and ocean have warmed, the amounts of snow and ice have diminished, and sea level has risen.

Anthropogenic greenhouse gas emissions have increased since the pre-industrial era…and are now higher than ever. This has led to atmospheric concentrations of carbon dioxide, methane and nitrous oxide that are unprecedented in at least the last 800,000 years. 

Continued emission of greenhouse gases will cause further warming and long-lasting changes in all components of the climate system, increasing the likelihood of severe, pervasive and irreversible impacts for people and ecosystems.

Limiting climate change would require substantial and sustained reductions in greenhouse gas emissions which, together with adaptation, can limit climate change risks.

It is very likely that heat waves will occur more often and last longer, and that extreme precipitation events will become more intense and frequent in many regions. The ocean will continue to warm and acidify, and global mean sea level to rise.

Climate change… risks…are generally greater for disadvantaged people and communities in countries at all levels of development.

Substantial emissions reductions over the next few decades can reduce climate risks in the 21st century and beyond, increase prospects for effective adaptation, reduce the costs and challenges of mitigation in the longer term, and contribute to climate-resilient pathways for sustainable development.

Without additional mitigation efforts beyond those in place today, and even with adaptation, warming by the end of the 21st century will lead to high to very high risk of severe, widespread, and irreversible impacts globally (high confidence). Mitigation involves some level of co-benefits and of risks due to adverse side-effects, but these risks do not involve the same possibility of severe, widespread, and irreversible impacts as risks from climate change, increasing the benefits from near-term mitigation efforts.

There are multiple mitigation pathways that are likely to limit warming to below 2°C [3.6°F] relative to pre-industrial levels. These pathways would require substantial emissions reductions over the next few decades and near zero emissions of CO2 and other long-lived GHGs by the end of the century. Implementing such reductions poses substantial technological, economic, social, and institutional challenges, which increase with delays in additional mitigation and if key technologies are not available.

I encourage you to dig into the full synthesis report for more detail. You may also want some information on how climate change is affecting your local area. For that, look to the solid, accessible findings of latest US National Climate Assessment, released this past spring.

Since the IPCC turned from review of new publications to synthesis last year, scientists at the Global Carbon Project reported that global emissions of carbon dioxide from fossil fuel burning and cement production reached record levels in 2013, rising 2.3% above the previous year and are projected to rise another 2.5% by the end of 2014. Emissions have now risen more than 60% since 1988, the year that the IPCC was formed and the scientific community’s concerns about climate change first received widespread public attention.

I hope this helps. You don’t have to be a scientist. Really. You just have to listen to them. And then draw upon their advice, your commitment to evidence-based decision-making, and your obligation to current constituents and future generations by getting to work ensuring that our nation is a leader in setting strong sensible climate policies.

I know you can do this.

Posted in: Energy, Global Warming

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  • Greyguy

    Using the IPCC may be offputting to many, because they had upwards of 15000 scientists initially supporting them and the number has dwindled to about one third of that [ballpark numbers]. When decision makers see that kind of drop in support it does not give them a warm feeling, they want to feel like they are leading a parade that is growing. Also many of the 10 statements are stated as facts when in truth they are in the hypothesis stage scientific methodology and when a politician senses that they were given a hard fact and discover the slightest soft spot they will panic….Science meets political pathology! This is especially true if any pain is associated with the 10 principles as they would be put in policy format; doubly true when 90 million Americans are not working or are under employed and might be asked to pay for these in someform or another.

  • Jen

    Policy makers aren’t puzzled by the science. They are puzzled about what can actually be done about it. This is one area where we could, if we would, possibly arrive at some practical compromises with policy makers. Let’s begin by offering accurate estimates of precisely how much sacrifice will be required to truly mitigate climate change. Knock it off with standard-issue nebulous statements like: “…multiple mitigation pathways…would…require near zero emissions of CO2 and other long-lived GHGs by the end of the century…”. Zero tolerance within the next 80 years, that’s what it will take…globally? Seriously? How off-putting is that? I mean, we are basically conceding it can’t be done. Why, then, would any reasonable person go along with any of the ineffective half-way measures some of our colleagues would impose on Americans who are already reeling from economic recession? The piddling regulatory measures we like to direct at selected political targets are easily recognized for the purely punitive efforts they really are. We are pissed because humans caused it and we can’t fix it but we definitely can single out key human enterprises to excoriate and punish. Certainly policy makers see through us, even without our enemies lobbying them. We need to stop underestimating the intelligence and integrity of policy makers and stop overestimating the veracity of our own popular wisdom. When policy makers ignore us they are only being polite. What they must really be thinking to themselves is “…oh, sit down and shut up…”, just like Gov. Christie actually dared to say. The political reality this week should not be lost on us.

  • Richard Solomon

    Thanks for a well meant, concise, and readable summary of the relevant elements in these reports on climate science. What’s lacking is the fact that our too many of leaders do not listen to this advice because of the influence that corporations which rely on fossil fuels have on decision making. Ie, these politicians are in the financial hip pocket of industries that are more invested in their short term financial bottom line than in the long term health of the planet. Thus, no substantial changes in policy can take place.

  • bdeye51

    If your focus is the ” baffled” politicians I think the use of anthropogenic in the 1st sentence of the #1 finding would be off-putting for many. Maybe next time.

  • Jai

    The IPCC projections have been shown to be overly conservative. Wide scale climate changes are already happening in the Amazon, the Arctic and in food producing regions all over the planet. These changes are happening far in advance of IPCC AR5 model projections. In addition, new evidence published within the last year show that AR5 sea level rise contributions from Antarctica are severely understated (Rignot et. al 2014) and that prior estimations of southern hemisphere ocean warming are also severely underestimated. (Durack et. al. 2014). The latter implies a much higher Equilibrium Climate Sensitivity (ECS) than that currently used by the AR5 and it also indicates that northern hemisphere aerosols have been much more effective in cooling the planet over the last 20 years than has been previously assumed.

    It must be stated, often and clearly that we are likely 40 years ahead of the IPCC AR5 damage estimates and that the final temperature rise for current emissions will become irreversible and catastrophic within the next 15 years. We have the will and the technology to make this transition, but only with concerted, collective effort. And we must, if future generations are going to survive into the 2060s.