Tag: Global Science Report

Thanks to Natural Gas and Climate Change, U.S. Carbon Dioxide Emissions Continue Downward Trend

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.”

Carbon dioxide emissions in the United States from the production and consumption of energy have been on the decline since about 2005, after generally being on the rise ever since our country was first founded.

The decline in emissions between 2012 and 2011 was 3.8 percent, which, according to the Energy Information Administration (EIA) was the largest decline in a non-recession year since 1990 and the first time that carbon dioxide (CO2) emissions fell while the per capita economic output increased by more than 2 percent.  In other words, we are producingmore while emitting less carbon dioxide.

 

Just in Time for Halloween Come Some Scary Global Warming Predictions

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.”

Global warming beater Justin Gillis of the New York Times had an article yesterday describing a new paper in the current issue of Nature magazine, the point of which seems to be scaring people with alarming global warming statistics.

Gillis’ article “By 2047, Coldest Years May Be Warmer Than Hottest in Past,” describes the results of a class-project-cum-Nature-article headed by Camilo Mora from the University of Hawaii at Manoa (please, no puns). The class assignment was to identify the year for each spot on the globe in which all future years were, according to climate model projections, warmer as a result of greenhouse gas emissions than the warmest year simulated by the models during the historical period 1860 to 2005. Mora and students termed this pivotal year the “climate departure.”

This work is significant, according to Gillis, because:

Thousands of scientific papers have been published about the model results, but the students identified one area of analysis that was missing. The results are usually reported as average temperature changes across the planet. But that gives little sense of how the temperature changes in specific places might compare with historical norms. “We wanted to give people a really relatable way to understand climate,” said Abby G. Frazier, a doctoral candidate in geography.

Perhaps Dr. Mora should have injected a little climate-science history in this class.

Looking at the time that a human climate signal will rise above the background noise is not particularly a novel concept. It’s commonplace. We would guess that a signal-to-noise ratio was probably present in the first papers describing the performance and output of the very first climate models.

After all, without such information it is impossible to put absolute changes in perspective.  Some measure of the statistical significance of climate change has been present in every climate assessment report from the U.N. Intergovernmental Panel on Climate Change dating back to 1990.

In our presentation to the Science Policy Conference of the American Geophysical Union this summer, we even included a table listing the number of years into the future it would be before projected changes in precipitation across the U.S. rose above the level of nature variability. We guess we just didn’t give that year a catchy enough name like “climate departure,” because our results didn’t capture the attention of the press (nor were they very frightening).

But Gillis does manage to carve some new, scary Jack-o-Lanterns from the Mora study.

Here is his lead paragraph:

If greenhouse emissions continue their steady escalation, temperatures across most of the earth will rise to levels with no recorded precedent by the middle of this century, researchers said Wednesday.

Uh, correct us if we are wrong, but we already thought that global temperatures were reported to be at unprecedented levels in recorded history. According to the IPCC’s Fifth Assessment Report:

Each of the last three decades has been successively warmer at the Earth’s surface than any preceding decade since 1850.

So, is this recycled news, or is the new paper saying that we have to wait until 2047 for that to happen? Well, whatever, it sounds B-A-D.

Or how about this one:

“Go back in your life to think about the hottest, most traumatic event you have experienced,” Dr. Mora said in an interview. “What we’re saying is that very soon, that event is going to become the norm.”

Hot Tub Time Machine came immediately to mind, but Gillis provided another scenario:

With the technique the Mora group used, it is possible to specify climate departure dates for individual cities. Under high emissions, climate departure for New York City will come in 2047, the paper found, plus or minus the five-year margin of error.

How scared should you be about passing the date of “climate departure”?

Not at all.

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.

 

New IPCC Report Will Be Internally Inconsistent and Misleading

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 Nation’s Intergovernmental Panel on Climate Change (IPCC) seems more intent on maintaining the crumbling “consensus” on anthropogenic global warming than on following climate science to its logical conclusion—a conclusion that increasingly suggests that human greenhouse gas emissions are less important in driving climate change than commonly held.

This fact is obvious from the embarrassing lack of internal inconsistency contained in the leaked versions of  the IPCC’s Fifth Assessment Report. The Summary for Policymakers, a succinct and brief document supposedly encapsulating what is in the entire 3,000-page report is supposed to be approved by closing time on Friday, at a meeting currently taking place in Stockholm.

In no place will this internal inconsistency be more obvious than in how the IPCC deals with the discrepancy between the observed effectiveness of greenhouse gases in warming the earth and this effectiveness calculated  by the climate models that the IPCC uses to project future climate change.

The warming effectiveness is known as the “climate sensitivity” and is the key parameter in how much the earth’s surface temperature rise as a result of the increasing atmospheric concentration of carbon dioxide and other greenhouse gases. Most all climate impacts are related to the climate sensitivity—the lower the climate sensitivity, the fewer the impacts.

One problem. Climate scientists don’t know what the value of the climate sensitivity really is.

Not because the calculation is complicated—just take how much the global average temperature has changed over some longish time period (a couple of decades or longer) and divide by much energy was used to force that change.

More IPCC Misdirection: Its Dodgy Sea Level-Rise Assessment

Global Science Report is a weekly 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 UN’s Intergovernmental Panel on Climate Change (IPCC) is set to release its Fifth Assessment Report (AR5) of the physical science of climate change at the conclusion on its editorial meeting in Stockholm scheduled from September 23-26th.

A version of its Summary for Policymakers (SPM)—perhaps the most influential portion of the report as it is the widest read—has been “leaked” to generate media interest in the upcoming release. It certainly has, but perhaps not in the manner intended. The leaked SPM has revealed a document so flawed and removed from current science that it has been described as not only being  “obsolete on the day that it is released, but that it will be dead wrong as well” (okay, we wrote that).

Examples already abound as to the problems evident in the leaked SPM. Here we add another—this one having to do with the recent rate of sea level rise.

In the Summary for Policymakers section of its Fourth Assessment Report (published in 2007) the IPCC had this to say about the rate of sea level rise:

Global average sea level rose at an average rate of 1.8 [1.3 to 2.3] mm per year over 1961-2003. The rate was faster over 1993 to 2003: about 3.1 [2.4 to 3.8] mm per year. Whether the faster rate for 1993 to 2003 reflects decadal variability or an increase in the longer-term trend is unclear.

Since then, we have highlighted numerous findings in the scientific literature that present strong evidence that the increase in the rate of sea level rise since 1993 is largely not an increase in the longer-term trend (or at least not from human-caused climate change which is the IPCC’s implication) and that the short-term rate of sea level rise has been slowing, and returning back towards the long-term average.

But the IPCC’s heart remains hardened.

The IPCC Is Pretty Much Dead Wrong

Global Science Report is a weekly 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.”

As the U.N.’s Intergovernmental Panel on Climate Change (IPCC) nears completion of its Fifth Assessment Report, it is becoming obvious that not only is the report going to obsolete on the day that it is released, but that it will be dead wrong as well.

We have discussed the implications of the IPCC’s failure to adequately ingest new literature—a failure that results partially from the cumbersome IPCC process and partly because the IPCC doesn’t want to include some findings that run counter to its storylines. The major implication being, of course, that the IPCC reports mislead policymakers around the world, which has a trickle-down effect on all of us who are subject to any resulting policies.

In our post on Monday, we noted the following passage from the “leaked” Summary for Policymakers of the upcoming Fifth Assessment Report:

[Climate] Models do not generally reproduce the observed reduction in surface warming trend over the last 10–15 years. There is medium confidence that this difference between models and observations is to a substantial degree caused by unpredictable climate variability, with possible contributions from inadequacies in the solar, volcanic, and aerosol forcings used by the models and, in some models, from too strong a response to increasing greenhouse-gas forcing. [italics in original]

We were generally pleased to see the IPCC admit that climate models are largely failing to capture the rate of rise (or lack thereof) of the global average surface temperature observed over the past 10-15 years. As we pointed out on Monday, we had written as much ourselves a few years ago.

But, the IPCC went way wrong in this paragraph in which they stated:

There is very high confidence that climate models reproduce the observed large-scale patterns and multi-decadal trends in surface temperature, especially since the mid-20th century. [italics in original]

No, they don’t.

Peer-reviewed or Not, the IPCC Accepts Our Conclusion

At the end of this month, the UN’s Intergovernmental Panel on Climate Change (IPCC) is scheduled to release the physical science basis of it Fifth Assessment Report on climate change. Between now and then, the final wording of its highly visible and influential Summary for Policymakers (SPM) will be hashed out in a meeting in Stockholm. The current draft version of the SPM has been “leaked” in order to drum up some media attention for the upcoming meeting/report.

Among many interesting statements in the draft SPM, this one particularly caught our eye:

[Climate] Models do not generally reproduce the observed reduction in surface warming trend over the last 10–15 years. There is medium confidence that this difference between models and observations is to a substantial degree caused by unpredictable climate variability, with possible contributions from inadequacies in the solar, volcanic, and aerosol forcings used by the models and, in some models, from too strong a response to increasing greenhouse-gas forcing. [italics in original, bold added by us]

We found this interesting because back in 2010, we, along with several co-authors, wrote a paper titled “Assessing the consistency between short-term global temperature trends in observations and climate model projections.” In that paper, we demonstrated  that climate models do not generally reproduce the observed reduction in surface warming trend over the last 10-15 years. We also wrote that this was the result of some combination of inadequacies in the evolution of anthropogenic forcing (including aerosols), natural variability (both that which is captured and that which is insufficiently handled by climate models), as well as the strong possibility that climate models were producing too much warming for a given amount of greenhouse gas emissions.

Specifically, we wrote: