intergovernmental panel on climate change

If People Are Like Polar Bears, We’ll Be Fine

Global Science Report is a feature from the Center for the Study of Science, where we highlight one or two important new items in the scientific literature or the popular media. For broader and more technical perspectives, consult our monthly “Current Wisdom.”

 

The United Nations’ Intergovernmental Panel on Climate Change (IPCC) is meeting in Japan this week to finalize the second part of its latest compendium on climate change.

The first part, the Working Group I report, focused on the physical science of climate change.  The main findings of that report, released last fall, have been widely panned for not telling the truth about how the latest science is stacking up in support of modest rather than alarming climate change.

The second part, making the news this week, is from the IPCC’s Working Group II and focuses on the effects of climate change.

In an interesting piece in a blog hosted by the United Kingdom’s The Telegraph, Andrew Lilico reports that if leaked drafts are to be trusted, the new report will mark a “formal moving on of the debate from the past, futile focus upon “mitigation” to a new debate about resilience and adaptation.”

We can only wonder what took them so long to realize this—something that we have been saying from virtually day one of this whole global warming thing.

That is not to say that the new IPCC report won’t proclaim that a whole lot of bad things are going to happen as a result of climate change. It most assuredly will say that. But, as we last reported, much of that concern is overblown hype.

Here is another example:

Climate Insensitivity: What the IPCC Knew and Didn’t Tell Us, Part II

Global Science Report is a feature from the Center for the Study of Science, where we highlight one or two important new items in the scientific literature or the popular media. For broader and more technical perspectives, consult our monthly “Current Wisdom.”

The bottom line from the new report from the Global Warming Policy Foundation (GWPF) is that the U.N.’s Intergovernmental Panel on Climate Change (IPCC) knew, but didn’t highlight, the fact that the best available scientific evidence suggests that the earth’s climate is much less sensitive to atmospheric carbon dioxide input than the climate models they relied upon  to forecast future global warming portray.

We covered the GWPF report and its implications in this post. But one implication is worth mentioning again, from the report’s conclusions:

The [climate models] overestimate future warming by 1.7–2 times relative to an estimate based on the best observational evidence.

While the report’s authors, Nicolas Lewis and Marcel Crok, are talking about the future, the same thing should apply to the past. In fact, a strong test of Lewis and Crok’s prediction is whether or not the same climate models predict too much warming to have already taken place than observations indicate.

There is perhaps a no better general assessment of past model behavior than the analysis that we developed for a post back in the fall.

The figure below is our primary finding. It shows how the observed rate of global warming compares with the rate of global warming projected to have occurred by the collection of climate models used by the IPCC. We performed this comparison over all time scales ranging from from 10 to 63 years. Our analysis ended in 2013 and included an analysis of the global temperature trend beginning in each year from 1950 through 2004. 

As can be clearly seen in our figure, climate models have consistently overestimated the amount of warming that has taken place. In fact, they are so bad, that over the course of the past 25 years (and even at some lengths as long as 35 years) the observed trend falls outside of the range which includes 95 percent of all model runs. In statistical parlance, this situation means that the observed trend cannot be reliably considered to be part of the collection of modeled trends. In other words, the real world is not accurately captured by the climate models—the models  predict that the world should warm up much faster than it actually does.

Climate Insensitivity: What the IPCC Knew But Didn’t Tell Us

Global Science Report is a feature from the Center for the Study of Science, where we highlight one or two important new items in the scientific literature or the popular media. For broader and more technical perspectives, consult our monthly “Current Wisdom.”

In a remarkable example of scientific malfeasance, it has become apparent that the IPCC knew a lot more than it revealed in its 2013 climate compendium about how low the earth’s climate sensitivity is likely to be.

The importance of this revelation cannot be overstated. If the UN had played it straight, the “urgency” of global warming would have evaporated, but, recognizing that this might cause problems, they preferred to mislead the world’s policymakers.

Strong words? Judge for yourself.

The report Oversensitive—how the IPCC hid the good news on global warming,” was released today by the Global Warming Policy Foundation (GWPF)—a U.K. think-tank which is “concerned about the costs and other implications of many of the policies currently being advocated” regarding climate change (disclosure: our Dick Lindzen is a member of the GWPF Academic Advisory Council).

The new GWPF report concluded:

We believe that, due largely to the constraints the climate model-orientated IPCC process imposed, the Fifth Assessment Report failed to provide an adequate assessment of climate sensitivity – either ECS [equilibrium climate sensitivity] or TCR [transient climate response] – arguably the most important parameters in the climate discussion. In particular, it did not draw out the divergence that has emerged between ECS and TCR estimates based on the best observational evidence and those embodied in GCMs. Policymakers have thus been inadequately informed about the state of the science.

The study was authored by Nicholas Lewis and Marcel Crok. Crok is a freelance science writer from The Netherlands and Lewis, an independent climate scientist, was an author on two recent important papers regarding the determination of the earth’s equilibrium climate sensitivity (ECS)—that is, how much the earth’s average surface temperature will rise as a result of a doubling of the atmospheric concentration of carbon dioxide.

The earth’s climate sensitivity is the most important climate factor in determining how much global warming will result from our greenhouse gas emissions (primarily from burning of fossil fuels to produce, reliable, cheap energy). But, the problem is, is that we don’t know what the value of the climate sensitivity is—this makes projections of future climate change–how should we say this?–a bit speculative.

Climate Models’ Tendency to Simulate Too Much Warming and the IPCC’s Attempt to Cover That Up

The Current Wisdom is a series of monthly articles in which Patrick J. Michaels and Paul C. “Chip” Knappenberger, from Cato’s Center for the Study of Science, review interesting items on global warming in the scientific literature that may not have received the media attention that they deserved, or have been misinterpreted in the popular press.

 

The biggest criticism to emerge so far regarding the new Fifth Assessment Report from the U.N.’s Intergovernmental Panel on Climate Change (IPCC) is that it generally fails to acknowledge how poorly climate model simulations of the earth’s temperature evolution compare with actual observations. If the models cannot accurately simulate known climate variability and change, using them for policy purposes is a fool’s errand.

There are two lines of evidence that converge to show that the climate models are largely failing to accurately simulate observed climate behavior.

The first is that a collection of about ten research papers (including 16 separate analyses) published in the scientific literature beginning in 2011 that collectively indicate that the earth’s equilibrium climate sensitivity—that is, how much the earth’s average surface temperature rises as a result of a doubling of the atmospheric carbon dioxide concentration—is about 2°C, give or take about 0.5°C (Figure 1). You can find details here

Figure 1. Climate sensitivity estimates from new research published since 2010 (colored), compared with range of estimates from the climate models incorporated into the IPCC Fifth Assessment Report (AR5; black). The arrows indicate the 5 to 95 percent confidence bounds for each estimate along with the best estimate (median of each probability density function; or the mean of multiple estimates; colored vertical line). Ring et al. (2012) present four estimates of the climate sensitivity and the red box encompasses those estimates. The light grey vertical bar is the mean of the 16 estimates from the new findings. The mean climate sensitivity (3.2°C) of the climate models used in the IPCC AR5 is 60 percent greater than the mean of recent estimates (2.0°C).

 

What the New IPCC Global Warming Projections Should Have Looked Like

Global Science Report is a feature from the Center for the Study of Science, where we highlight one or two important new items in the scientific literature or the popular media. For broader and more technical perspectives, consult our monthly “Current Wisdom.”

The United Nations’ Intergovernmental Panel on Climate Change (IPCC) released its Fifth Assessment Report (AR5) last week to fanfare and stinging criticism.

Most of the criticism was aimed at the IPCC’s defense of climate models—models that the latest observations of the earth’s climate evolution show to be inaccurate, or at least are strongly indicative that is the case.

There are two prominent and undeniable examples of the models’ insufficiencies: 1) climate models overwhelmingly expected much more warming to have taken place over the past several decades than actually occurred; and 2) the sensitivity of the earth’s average temperature to increases in atmospheric greenhouse gas concentrations (such as carbon dioxide) averages some 60 percent greater in the IPCC’s climate models than it does in reality (according to a large and growing collection of evidence published in the scientific literature).

Had the IPCC addressed these model shortcomings head on, the flavor of their entire report would have been different. Instead of including projections for extreme climate changes as a result of continued human emissions of greenhouse gases resulting from our production of energy, the high-end projections would have featured relatively modest changes and the low-end projections would have been completely unremarkable.

Since changes in the earth’s temperature scale approximately linearly with a property known as the earth’s equilibrium climate sensitivity (how much the earth’s average surface temperature rises as a result of a doubling of the atmosphere’s carbon dioxide concentration), it is pretty straightforward to adjust the IPCC’s projections of future temperature change to bring them closer to what the latest science says the climate sensitivity is. That science suggests the equilibrium climate sensitivity probably lies between 1.5°C and 2.5°C (with an average value of 2.0°C), while the climate models used by the IPCC have climate sensitivities which range from 2.1°C to 4.7°C with an average value of 3.2°C.

To make the IPCC projections of the evolution of the earth’s average temperature better reflect the latest scientific estimates of the climate sensitivity, it is necessary to adjust them downward by about 30% at the low end, about 50% at the high end, and about 40% in the middle.

The figure below the jump shows what happens when we apply such a correction (note: we maintain some internal weather noise). The top panel shows the projections as portrayed by the IPCC in their just-released Fifth Assessment Report, and the lower panel shows what they pretty much would have looked like had the climate models better reflected the latest science. In other words, the lower panel is what the IPCC temperature projections should have looked like.

 

Band-aids Can’t Fix the New IPCC Report

The U.N.’s Intergovernmental Panel on Climate Change (IPCC) today released the Summary for Policymakers (SPM) of the physical science volume of its Fifth Assessment Report. The SPM is the most widely-read section of the IPCC reports and purports to summarize and highlight the contents of the thousand-odd pages of the full report. The SPM is agreed to word by word by the international attendees of the IPCC’s final editorial meeting which concluded as the SPM was released.

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