Tag: climate change

Fatal Flaw in the USGCRP Climate and Health Assessment

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.”

 

Yesterday, we posted some excerpts from the Background section of our submitted Comment on the draft report on climate and health from the U.S. Global Change Research Program (USGCRP). In that section, we argued that the USGCRP was overlooking (ignoring?) a vital factor that shapes the influence of climate change on the health and well-being of Americans—that is, that the adaptive process is actually spurred by climate change itself. Without recognition of this fact, projections are often alarmist and pessimistic.

Today, we wanted to highlight what we found to be the fatal flaw in the entire USGCRP report—that the USGCRP fails to describe the net impact of climate change on public health, instead, presenting only a narrow and selective look at what they determine to be negative impacts (and even those examples tend to be miscast).

Here’s what we had to say about this:

Comments on the USGCRP Climate and Health Assessment

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.”

On June 8th, the public comment period on the draft report on climate and health from the U.S. Global Change Research Program (USGCRP) closed. Never liking to miss an opportunity to add our two cents’ worth to the conversation, we submitted a set of comments that focused on the weakness of the underlying premise of the report, more so than the specific details (although we did include a sample set of those to show just how pervasive the selective and misuse of science is throughout the report).

Our entire Comments are available here. But, for convenience, here’s the highlight reel. In summary, we found:

What is clear from this report, The Impacts of Climate Change on Human Health in the United States: A Scientific Assessment, and all other similar ones that have come before, is that the USGCRP simply chooses not to accept the science on human health and climate and instead prefers to forward alarming narratives, many based on science fiction rather than actual science. To best serve the public, this report should be withdrawn. By going forward without a major overhaul, its primary service [will] be to misinform and mislead the general public and policymakers alike.

Here we lay out the general problem:

The authors of the USGCRP draft of The Impacts of Climate Change on Human Health in the United States: A Scientific Assessment report have an outstanding imagination for coming up with ways that climate change may negatively impact the health and well-being of Americans, but a profound lack of understanding in the manner in which health and well-being is impacted by climate (including climate change).

Spin Cycle: Whither the Hiatus

The Spin Cycle is a reoccurring feature based upon just how much the latest weather or climate story, policy pronouncement, or simply poo-bah blather spins the truth. Statements are given a rating between 1-5 spin cycles, with less cycles meaning less spin. For a more in-depth description, visit the inaugural edition.

Today’s press buzz is about a new paper appearing in this week’s Science magazine which concludes that the “hiatus” in global warming is but a byproduct of bad data. The paper, “Possible artifacts of data biases in the recent global surface warming hiatus,” was authored by a research team led by Director of the National Oceanic and Atmospheric Administration’s National Climatic Data Center, Dr. Thomas Karl. Aside from missing the larger point—that the relevant question is not whether the earth is warming, but why it’s warming so much slower than the computer model projections—the paper’s conclusions have been well-run through the spin cycle.

The spin was largely conducted by the American Association for the Advancement of Science (AAAS), publisher of Science magazine, through its embargo campaign and the courting of major science writers in the media before the article had been made available to the general public (and other scientists). Given the obvious weaknesses in the new paper (see below and here, for starters), there seems the potential for more trouble at Science—something that Editor-in-Chief Marcia McNutt is up to her eyeballs with already.

One major problem with the new Karl and colleagues paper is that the headline-making finding turns out not even to be statistically significant at the standard scientific level—that is, having a less than 1-in-20 chance of being due to chance (unexplained processes) alone.

Instead, the results are reported as being “statistically significant” if they have less than a 1-in-10 chance of being caused by randomness.

More and more we are seeing lax statistical testing being applied in high profile papers (see here and here for recent examples). This tendency is extremely worrisome, as at the same time, the validity of large portions of the scientific literature is being questioned on the basis of (flawed) methodological design and poor application and interpretation of statistics. An illuminating example of how easily poor statistics can make it into the scientific literature and produce a huge influence on the media was given last week in the backstory of a made-up paper claiming eating chocolate could enhance weight loss efforts.

But, as the Karl et al. paper (as well as the other recent papers linked above) shows, some climate scientists are pushing forward with less than robust results anyway.

Why? Here’s a possible clue.

Recall an op-ed in the New York Times a few months back by Naomi Oreskes titled “Playing Dumb on Climate Change.” In it, Oreskes, a science historian (and author of the conspiratorial Merchants of Doubt) argued that since climate change was such an urgent problem, we shouldn’t have to apply the same 1-in-20 set of rigorous statistics to the result—it is slowing down the push for action. Climate scientists, Oreskes argued, were being too conservative in face of a well-known threat and therefore, “lowering the burden of proof” should be acceptable.

Is There No “Hiatus” in Global Warming After All?

A new paper posted today on ScienceXpress (from Science magazine), by Thomas Karl, Director of NOAA’s Climate Data Center, and several co-authors[1], that seeks to disprove the “hiatus” in global warming prompts many serious scientific questions.

The main claim[2] by the authors that they have uncovered a significant recent warming trend is dubious. The significance level they report on their findings (.10) is hardly normative, and the use of it should prompt members of the scientific community to question the reasoning behind the use of such a lax standard.

In addition, the authors’ treatment of buoy sea-surface temperature (SST) data was guaranteed to create a warming trend. The data were adjusted upward by 0.12°C to make them “homogeneous” with the longer-running temperature records taken from engine intake channels in marine vessels. 

As has been acknowledged by numerous scientists, the engine intake data are clearly contaminated by heat conduction from the engine itself, and as such, never intended for scientific use. On the other hand, environmental monitoring is the specific purpose of the buoys. Adjusting good data upward to match bad data seems questionable, and the fact that the buoy network becomes increasingly dense in the last two decades means that this adjustment must put a warming trend in the data.

The extension of high-latitude arctic land data over the Arctic Ocean is also questionable. Much of the Arctic Ocean is ice-covered even in high summer, meaning the surface temperature must remain near freezing. Extending land data out into the ocean will obviously induce substantially exaggerated temperatures.

Additionally, there exist multiple measures of bulk lower atmosphere temperature independent from surface measurements which indicate the existence of a “hiatus”[3]. If the Karl et al., result were in fact robust, it could only mean that the disparity between surface and mid-tropospheric temperatures is even larger that previously noted. 

Getting the vertical distribution of temperature wrong invalidates virtually every forecast of sensible weather made by a climate model, as much of that weather (including rainfall) is determined in large part by the vertical structure of the atmosphere.

Instead, it would seem more logical to seriously question the Karl et al. result in light of the fact that, compared to those bulk temperatures, it is an outlier, showing a recent warming trend that is not in line with these other global records.

And finally, even presuming all the adjustments applied by the authors ultimately prove to be accurate, the temperature trend reported during the “hiatus” period (1998-2014), remains significantly below (using Karl et al.’s measure of significance) the mean trend projected by the collection of climate models used in the most recent report from the United Nation’s Intergovernmental Panel on Climate Change (IPCC). 

It is important to recognize that the central issue of human-caused climate change is not a question of whether it is warming or not, but rather a question of how much. And to this relevant question, the answer has been, and remains, that the warming is taking place at a much slower rate than is being projected.

The distribution of trends of the projected global average surface temperature for the period 1998-2014 from 108 climate model runs used in the latest report of the U.N.’s Intergovernmental Panel on Climate Change (IPCC)(blue bars). The models were run with historical climate forcings through 2005 and extended to 2014 with the RCP4.5 emissions scenario. The surface temperature trend over the same period, as reported by Karl et al. (2015, is included in red. It falls at the 2.4th percentile of the model distribution and indicates a value that is (statistically) significantly below the model mean projection.

The distribution of trends of the projected global average surface temperature for the period 1998-2014 from 108 climate model runs used in the latest report of the U.N.’s Intergovernmental Panel on Climate Change (IPCC)(blue bars). The models were run with historical climate forcings through 2005 and extended to 2014 with the RCP4.5 emissions scenario. The surface temperature trend over the same period, as reported by Karl et al. (2015, is included in red. It falls at the 2.4th percentile of the model distribution and indicates a value that is (statistically) significantly below the model mean projection.


[1] Karl, T. R., et al., Possible artifacts of data biases in the recent global surface warming hiatus. Scienceexpress, embargoed until 1400 EDT June 4, 2015.

[2] “It is also noteworthy that the new global trends are statistically significant and positive at the 0.10 significance level for 1998-2012…”

[3] Both the UAH and RSS satellite records are now in their 21st year without a significant trend, for example

You Ought to Have a Look: Climate Change Subtleties, Hurricanes, and Chocolate Bunnies

You Ought to Have a Look is a feature from the Center for the Study of Science posted by Patrick J. Michaels and Paul C. (“Chip”) Knappenberger.  While this section will feature all of the areas of interest that we are emphasizing, the prominence of the climate issue is driving a tremendous amount of web traffic.  Here we post a few of the best in recent days, along with our color commentary.

We highlight a couple of headlines this week that made us chuckle a bit, although what they portend is far from funny.

The first was from the always amusing “Energy and Environment” section of the Washington Post. Climate change beat writer Chris Mooney penned a piece headlined “The subtle — but real — relationship between global warming and extreme weather events” that was a hit-you-over-the-head piece about how human-caused global warming could be linked to various weather disasters of the past week, including the floods in Houston, the heatwave in India and hurricanes in general.

Mooney starts out, lamenting:

Last week, some people got really mad at Bill Nye the Science Guy. How come? Because he had the gall to say this on Twitter:

Billion$$ in damage in Texas & Oklahoma. Still no weather-caster may utter the phrase Climate Change.

Nye’s comments, and the reaction to them, raise a perennial issue: How do we accurately parse the relationship between climate change and extreme weather events, as they occur in real time?

It’s a particularly pressing question of late, following not only catastrophic floods in Texas and Oklahoma, but also a historic heatwave in India that has killed over 2,000 people so far, and President Obama’s recent trip to the National Hurricane Center in Miami, where he explicitly invoked the idea that global warming will make these storms worse (which also drew criticism).

As the Nye case indicates, there is still a lot of pushback whenever anyone dares to link climate change to extreme weather events. But we don’t have to be afraid to talk about this relationship. We merely have to be scrupulously accurate in doing so, and let scientists lead the way.

The Spin Cycle: Accelerating Sea Level Rise

The Spin Cycle is a reoccurring feature based upon just how much the latest weather or climate story, policy pronouncement, or simply poo-bah blather spins the truth. Statements are given a rating between 1-5 spin cycles, with less cycles meaning less spin. For a more in-depth description, visit the inaugural edition.

A popular media story of the week was that sea level rise was accelerating and that this was worse than we thought. The stories were based on a new paper published in the journal Nature Climate Change by an author team led by the University of Tasmania’s Christopher Watson.

Watson and colleagues re-examined the satellite-based observations of sea level rise (available since the early 1990s) using a new methodology that supposedly better accounts for changes in the orbital altitude of the satellites—obviously a key factor when assessing sea levels by determining the height difference between the ocean’s surface and the satellites, the basic idea behind altimetry-based sea level measurements.

So far so good.

Their research produced two major findings, 1) their new adjusted measurements produced a lower rate of sea level rise than the old measurements (for the period 1993 to mid-2014), but 2) the rate of sea level rise was accelerating.

It was the latter that got all of the press.

But, it turns out, that in neither case, were the findings statistically significant at even the most basic levels used in scientific studies. Generally speaking, scientists report a findings as being “significant” if there is a less than 1-in-20 chance that the same result could have been produced by random (i.e., unexplained) processes. In some fields, the bar is set even higher (like 1 in 3.5 million). We can’t think of any scientific field that accepts a lower than a 1-in-20 threshold (although occasional individual papers do try to get away with applying a slightly lower standard).

Climate Change Concerns Don’t Belong in Dietary Guidelines

On Friday, May 8, the public comment period closed for the new 2015 Dietary Guidelines issued by the U.S. Department of Agriculture (USDA) and the Department of Health and Human Services (HHS). In a nutshell, the new dietary guidelines are to eat a diet richer in plant-based foods and leaner in animal-based products. One of the considerations used by the USDA/HHA in their Scientific Report used to rationalize these new dietary guidelines was that such diets are

“associated with more favorable environmental outcomes (lower greenhouse gas emissions and more favorable land, water, and energy use) than are current U.S. dietary patterns.” [emphasis added]

Throughout the Scientific Report whenever greenhouse gases are mentioned, a negative connotation is attached and food choices are praised if they lead to reduced emissions.

This is misleading on two fronts. First, the dominant greenhouse gas emitted by human activities is carbon dioxide which is a plant fertilizer whose increasing atmospheric concentrations have led to more productive plants, increasing total crop yields by some 10-15 percent to date. The USDA/HHS is at odds with itself in casting a positive light on actions that are geared towards lessening a beneficial outcome for plants, while at the same time espousing a more plant-based diet.

And second, the impact that food choices have on greenhouse gas emissions is vanishingly small—especially when cast in terms of climate change. And yet it is in this context that the discussion of GHGs is included in the Scientific Report. The USDA/HHS elevates the import of GHG emissions as a consideration in dietary choice far and above the level of its actual impact.

In our Comment to the USDA/HHS, we attempted to set them straight on these issues.

Our full Comment is available here, but for those looking for a synopsis, here is the abstract:

There are really only two reasons to discuss greenhouse gas emissions (primarily carbon dioxide) in the context of dietary guidelines in the U.S., and yet the USDA and HHS did neither in their Scientific Report of the 2015 Dietary Guidelines Advisory Committee (DGAC).

The first reason would be to discuss how the rising atmospheric concentration of CO2—a result primarily of the burning of fossil fuels to produce energy—is a growing benefit to plant life. This is an appropriate discussion in a dietary context as atmospheric CO2 is a fertilizer that promotes healthier, more productive plants, including crops used directly as food for humans or indirectly as animal feed. It has been estimated that from the atmospheric CO2 enrichment to date, total crop production as increased by 10-15 percent. This is a positive and beneficial outcome and one that most certainly should be included in any discussion of the role of greenhouse gases emissions in diet and nutrition—but is inexplicably lacking from such discussion in the DGAC report.

The second reason to discuss greenhouse gas emissions in a diet and nutrition report would be to dispel the notion that through your choice of food you can “do something” about climate change.  In this context, it would be appropriate to provide a quantitative example of how the dietary changes recommended by the DGAC would potentially impact projections of the future course of the climate. Again, the DGAC failed to do this.  We help fill this oversight with straightforward calculation of averted global warming that assumes all Americans cut meat out of their diet and become vegetarians—an action that, according to the studies cited by the DGAC, would have the maximum possible impact on reducing greenhouse gas emissions and thus mitigating future climate change.  Even assuming such an unlikely occurrence, the amount of global warming that would be averted works out to 0.01°C (one hundredth of a degree) by the end of the 21st century.  Such an inconsequential outcome has no tangible implications.  This should be expressed by the DGAC and mention of making dietary changes in the name of climate change must be summarily deleted.

We recommend that if the DGAC insists on including a discussion of greenhouse gas emissions (and thus climate change) in it 2015 Dietary Guidelines, that the current discussion be supplemented, or preferably replaced, with a more accurate and applicable one—one that indicates that carbon dioxide has widespread and near-universal positive benefits on the supply of food we eat, and that attempting to limit future climate change through dietary choice is misguided and unproductive.  These changes must be made prior to the issuance of the final guidelines. 

We can only guess on what sort of impact our Comment will have, but we can at least say we tried.