Tag: climate sensitivity

Climate Alarmism: When Is This Bozo Going Down?

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.”

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Climate alarmism is like one of those pop-up Bozos. No matter how many times you bop it, up it springs. In fact, the only way to stop it, as most kids learn, is to deflate it. In this case, the air inside Bozo is your and my tax money.

Two scientific papers released last week combine for a powerful 1-2 haymaker, but, rest assured, Bozo springs eternal. The first says that human aerosol emissions are not that responsible for offsetting the warming influence of greenhouse gas emissions, while the second finds that the observed warming from human greenhouse gases is less than a lot of people think.

We aren’t at all surprised by the first result.  The cooling effect of sulphate particulates, which go into the air along with carbon dioxide when fossil fuels (mainly coal) are combusted, was only invoked in the mid-1980s, when the lack of warming predicted by computer models was embarrassingly obvious.

This is the kind of thing that the iconic historian of science, Thomas Kuhn, predicted in his classic book, The Structure of Scientific Revolutions. When a scientific “paradigm” is assaulted by reality, increasingly ornate and bizarre explanations are put forth to keep it alive. Sulfates smelled like one of those to us back in the 1980s, and now it looks like the excuses are finally getting comeuppance.

The second result also comes as little news to us, as we have been saying for years that the human carbon dioxide emissions are not the only player in the climate change game.

The two new papers, in combination, mean that the human influence on the climate from the burning of fossil fuels is far less than what the IPCC’s ensemble of climate models says it is. This also goes for the U.S. Global Change Research Program, the EPA ,and the White House.

Rest assured, though, Bozo will rise again—despite a near-continuous barrage of blows supporting the idea that the climate’s sensitivity to human greenhouse gas emissions is far too low to justify any of the expensive and futile actions emanating from Washington and Brussels.

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.

More Evidence for a Low Climate Sensitivity

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.”

We have two new entries to the long (and growing) list of papers appearing the in recent scientific literature that argue that the earth’s climate sensitivity—the ultimate rise in the earth’s average surface temperature from a doubling of the atmospheric carbon dioxide content—is close to 2°C, or near the low end of the range of possible values presented by the U.N.’s Intergovernmental Panel on Climate Change (IPCC).  With a low-end warming comes low-end impacts and an overall lack of urgency for federal rules and regulations (such as those outlined in the President’s Climate Action Plan) to limit carbon dioxide emissions and limit our energy choices.

The first is the result of a research effort conducted by Craig Loehle and published in the journal Ecological Modelling. The paper is a pretty straightforward determination of the climate sensitivity.  Loehle first uses a model of natural modulations to remove the influence of natural variability (such as solar activity and ocean circulation cycles) from the observed temperature history since 1850. The linear trend in the post-1950 residuals from Loehle’s natural variability model was then assumed to be largely the result, in net, of human carbon dioxide emissions.  By dividing the total temperature change (as indicated by the best-fit linear trend) by the observed rise in atmospheric carbon dioxide content, and then applying that relationship to a doubling of the carbon dioxide content, Loehle arrives at an estimate of the earth’s transient climate sensitivity—transient, in the sense that at the time of CO2 doubling, the earth has yet to reach a state of equilibrium and some warming is still to come. 

Loehle estimated the equilibrium climate sensitivity from his transient calculation based on the average transient:equilibrium ratio projected by the collection of climate models used in the IPCC’s most recent Assessment Report. In doing so, he arrived at an equilibrium climate sensitivity estimate of 1.99°C with a 95% confidence range of it being between 1.75°C and 2.23°C.

Compare Loehle’s estimate to the IPCC’s latest assessment of the earth’s equilibrium climate sensitivity which assigns a 66 percent or greater likelihood that it lies somewhere in the range from 1.5°C to 4.5°C. Loehle’s determination is more precise and decidedly towards the low end of the range.

The second entry to our list of low climate sensitivity estimates comes from  Roy Spencer and William Braswell and published in the Asia-Pacific Journal of Atmospheric Sciences. Spencer and Braswell used a very simple climate model to simulate the global temperature variations averaged over the top 2000 meters of the global ocean during the period 1955-2011. They first ran the simulation using only volcanic and anthropogenic influences on the climate. They ran the simulation again adding a simple take on the natural variability contributed by the El Niño/La Niña process. And they ran the simulation a final time adding in a more complex situation involving a feedback from El Niño/La Niña onto natural cloud characteristics. They then compared their model results with the set of real-world observations.

What the found, was the that the complex situation involving El Niño/La Niña feedbacks onto cloud properties produced the best match to the observations.  And this situation also produced the lowest estimate for the earth’s climate sensitivity to carbon dioxide emissions—a value of 1.3°C.

Spencer and Braswell freely admit that using their simple model is just the first step in a complicated diagnosis, but also point out that the results from simple models provide insight that should help guide the development of more complex models, and ultimately could help unravel some of the mystery as to why full climate models produce  high estimates of the earth’s equilibrium climate sensitivity, while estimates based in real-world observations are much lower.

Our Figure below helps to illustrate the discrepancy between climate model estimates and real-world estimates of the earth’s equilibrium climate sensitivity. It shows Loehle’s determination as well as that of Spencer and Braswell along with 16 other estimates reported in the scientific literature, beginning in 2011. Also included in our Figure is both the IPCC’s latest assessment of the literature as well as the characteristics of the equilibrium climate sensitivity from the collection of climate models that the IPCC uses to base its impacts assessment.

Figure 1. Climate sensitivity estimates from new research beginning in 2011 (colored), compared with the assessed range given in the Intergovernmental Panel on Climate Change (IPCC) Fifth Assessment Report (AR5) and the collection of climate models used in the IPCC AR5. The “likely” (greater than a 66% likelihood of occurrence)range in the IPCC Assessment is indicated by the gray bar. 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 right-hand side of the IPCC AR5 range is actually the 90% upper bound (the IPCC does not actually state the value for the upper 95 percent confidence bound of their estimate). Spencer and Braswell (2013) produce a single ECS value best-matched to ocean heat content observations and internal radiative forcing.

Quite obviously, the IPCC is rapidly losing is credibility.

As a result, the Obama Administration would do better to come to grips with this fact and stop deferring to the IPCC findings when trying to justify increasingly  burdensome  federal regulation of  carbon dioxide emissions, with the combined effects of manipulating markets and restricting energy choices.

References:

Loehle, C., 2014. A minimal model for estimating climate sensitivity. Ecological Modelling, 276, 80-84.

Spencer, R.W., and W. D. Braswell, 2013. The role of ENSO in global ocean temperature changes during 1955-2011 simulated with a 1D climate model. Asia-Pacific Journal of Atmospheric Sciences, doi:10.1007/s13143-014-0011-z.

‘Worse Than We Thought’ Rears Ugly Head Again

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.”


Our last post was a brief run-through of some items of interest from the recent scientific literature that buck the popular alarmist meme that human-caused climate change is always “worse than we thought.” But as we said in that post, finding coverage of such results in the dinosaur media is a fool’s errand. Instead, it thrives on “worse than we thought” stories, despite their becoming a detriment to science itself.

Not to disappoint, headlines from the first major climate change story of the new year claim “Climate change models underestimate likely temperature rise, report shows,” and it’s clearly Worse Than We Thought. In its January 5 (Sunday) paper, the editorial board of the Washington Post points to the new results as a call for action on climate change.

The trumpeted results appear in a paper published in the January 2nd 2014 issue of Nature magazine by a team led by University of New South Wales professor Steven Sherwood and colleagues which claims that the earth’s equilibrium climate sensitivity—how much the global average surface temperature will rise as a result of a doubling of the atmospheric carbon dioxide content—is being underestimated by most climate models. Sherwood’s team finds “a most likely climate sensitivity of about 4°C, with a lower limit of about 3°C.”

Sherwood’s most likely value of 4°C is about twice the value arrived at by a rather largish collection of other research published during the past 2-3 years and lies very close to the top of the likely range (1.5°C to 4.5°C) given in the new report from the U.N.’s Intergovernmental Panel on Climate Change (IPCC).

While there are a host of reasons as to why our understanding of the true value of the climate sensitivity is little better constrained now that it was some 20+ years ago (it was given as 1.5°C to 4.5°C in the IPCC’s first report issued, almost a quarter-century ago), it is widely recognized that our understanding of the role of clouds in a changing climate is central to the issue.

In describing the why climate models have such different climate sensitivity values, the IPCC writes, in the 2013 edition of it’s science compendium,

There is very high confidence that uncertainties in cloud processes explain much of the spread in modelled climate sensitivity.

Sherwood and colleague set out to see if they could help nail down the specific cloud processes involved in the model spread and to see if recent observations could help better understand which models were handling  processes related to cloud behavior better than others.

Low Climate Sensitivity Making its Way into the Mainstream Press

When it comes to the press, the New York Times pretty much defines “mainstream.”

And Justin Gillis is the Times’ mainstream reporter on the global warming beat.

So it is somewhat telling, that his article on Tuesday, “A Change in Temperature,” was largely dedicated (although begrudgingly) to facing up to the possibility that mainstream estimates (i.e., those produced by the U.N.’s Intergovernmental Panel on Climate Change) of climate sensitivity are too large.

Readers of this blog are probably well aware of the reasons why.

Despite our illusions of grandeur, this blog isn’t the mainstream press –although we do seek to influence it. Maybe we are being successful.

Throughout Gillis’ article are sprinkled references to “climate contrarians,” and even the recognition of the effort by such contrarians to push the new science on low climate sensitivity to the forefront of the discussion to change the existing politics of climate change.

Gillis writes:

Still, the recent body of evidence — and the political use that climate contrarians are making of it to claim that everything is fine — sheds some light on where we are in our scientific and public understanding of the risks of climate change.

We at the Cato’s Center for the Study of Science are at the leading edge of efforts to present a more accurate representation of the scientific of climate change through our testimony to Congress, public comments and review of government documents and proposals, media appearances, op-eds, and serial posts on this blog, among other projects. We emphasize that current regulations and proposed legislation are based on outdated, and likely wrong, projections of future climate impacts from human carbon dioxide emissions from the use of fossil fuels to produce energy.

Gillis recognizes the positives of a low climate sensitivity value:

“…tantalizing possibility that climate change might be slow and limited enough that human society could adapt to it without major trauma.”

“It will certainly be good news if these recent papers stand up to critical scrutiny, something that will take at least a year or two to figure out.”

“So if the recent science stands up to critical examination, it could indeed turn into a ray of hope…”

But, the “mainstream” is slow to change. And so despite the good news about climate sensitivity, Gillis closes his article by pointing out that, in his opinion, the political response to climate change has been “weak” (contrary to our view), and that therefore:

Even if climate sensitivity turns out to be on the low end of the range, total emissions may wind up being so excessive as to drive the earth toward dangerous temperature increases.

Clearly we still have work to do, but there are signs of progress!