Tag: climate science

Heavy Rains Increasing, but Not Disproportionately So

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.”

A new paper has been published in the journal Geophysical Research Letters that examines trends in heavy rainfall amounts across the U.S. The paper is authored by Newcastle University’s Renaud Barbero and colleagues, and, to summarize, finds that the heaviest rainfall events of the year have been increasing in magnitude since 1951 when averaged across nearly 500 stations distributed across the U.S. (note: results from individual stations may differ from the general finding).

Someone with a critical eye might ask the real question, which is “how much?” That such a number does not jump out of this paper—a cynic would say—probably means it is very small. Read on and you will find the answer.

That rainfall on the rainiest day of the year is increasing is, of itself, hardly surprising considering that the total annual rainfall amount averaged across the U.S. has also been increasing during this same period (again, results from individual locations/regions may (and do) depart from this generality).

Changes in heavy rainfall like this are often luridly described as a “disproportionate increase” in extreme events, or that extreme precipitation increases are “worse than expected.”

You Ought to Have a Look: How to Properly Worry about Climate Change, aka, Lukewarming

You Ought to Have a Look is a regular feature from the Center for the Study of Science.  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.

In our last episode of You Ought to Have a Look (which was prominently quoted in an editorial in Nature magazine this week), we looked at reasons why folks who are wishing climate change mitigation should be the driving force behind most federal regulations should be very worried about what the incoming Trump Administration has in store. Most of his announced agency heads, etc., don’t share their vision (unlike those currently running the Obama Administration).

This week we start off with a guide to how folks should worry about climate change in general. Is it really true that, according to President Obama, “No challenge—no challenge—poses a greater threat to future generations than climate change”? The short answer is no. The long answer is provided by Manhattan Institute’s Oren Cass is his recent piece for National Affairs called “How to Worry about Climate Change”.

Oren describes how climate change is different from typical political policy questions:

Climate change is a different kind of problem from health-care reform, gender equality, or almost any traditional subject of political attention and action. Its relevant effects are still decades or centuries away. Scenarios with the most extreme effects, rather than the most likely ones, provide the sense of urgency and the rationale for policy responses. Those extreme outcomes are often distant ripples from the initial effect of a warmer climate, transmitted outward through multiple steps of causation and combined with other factors to produce or amplify the damage. By the time actual impacts arrive, the time for action may have long passed. But if climate change is not a typical policy problem, how should policymakers approach it?

…Yes, climate change is a problem. But what kind of problem?

He then sets out to answer that question:

Climate change—forecasted, irreversible, and pervasive—might therefore be called a “worrying problem.” Here, “worrying” does not mean “concerning” (though it is that as well), but rather something tailor-made for worry. Its effects exist primarily in the imagination and have poorly defined bounds that encourage speculation; a point of no return looms. Yet the contours of those bounds and that point may become clear only after it is too late to correct course.

Other worrying problems exist. They tend to emerge where clear long-term trends in technological or social change produce concerning side effects.

Oren provides other examples of “worrying problems” such as a global pandemic caused by international travel and urbanization, overuse of antibiotics, nuclear weapons, interconnectivity of financial systems, democratization of communications technologies, computer viruses, superhuman computer intelligence, weaponized nanotechnology, and many more, including social ones, as well as the sustainability of the Western welfare state itself. As Oren says there is “much to worry about,” but reminding everyone that “we should heed the well-known warning: ‘What worries you masters you.’”

Some Climate Realities for the Incoming Administration to Consider

While the twitterverse is chirping with concern over Donald Trump’s handling of the global warming science, we offer a few realities that should be key parts of any transitional team’s synthesis.

1. Carbon dioxide is a greenhouse gas that by itself will result in a slight warming of the lower atmosphere and surface temperatures, as well as a cooling of the stratosphere.

     a. All of these have been observed.

 2. Additional warming is provided by a complicated feedback with water vapor. If it were large and positive, so would be future warming.

     a. The observed warming is far below values consistent with a high temperature sensitivity. Therefore future warming will run considerably below any high-sensitivity estimate.

     b. The disparity between observed and forecast warming continues to grow.

You Ought to Have a Look: The Interface of Climate Change Science and Climate Change Policy

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 came across a pair of interesting, but somewhat involved reads this week on the interface of science and science policy when it comes to climate change. We’ll give you a little something to chew on from each one, but suggest that you ought you have a look at them at length to appreciate them in full.

First up is a piece, “The Limits of Knowledge and the Climate Change Debate” appearing in the Fall 2016 issue of the Cato Journal by Brian J. L. Berry, Jayshree Bihari, and Euel Elliott in which the authors examine the “increasingly contentious confrontation over the conduct of science, the question of what constitutes scientific certainty, and the connection between science and policymaking.”

You Ought to Have a Look: Intimidation in Science

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.

Talk of interference, intimidation, and abridgement of scientific freedom continues to make the news this week—and increasingly is taking the form of pushback against recently announced congressional investigations into sources of scientific research funding.

On Tuesday, the Wall Street Journal ran an editorial offering a “round of applause for those pushing back, providing the bullies a public lesson in the First Amendment.” Highlighted in their coverage were efforts by the Cato Institute, Heartland Institute and Koch Industries condemning attempts to “silence public debate” on climate change. From the WSJ:

Democrats and their allies have failed to persuade Americans that climate change is so serious that it warrants sweeping new political controls on American energy and industry. So liberals are trying to silence those who are winning the argument. We’re glad to see the dissenters aren’t intimidated.

Also unintimidated by attempts abridge academic freedom is Alice Dreger, professor of Medical Education-Medical Humanities and Bioethics at Northwestern University and a historian of science and medicine. Dreger has a new book out titled Galileo’s Middle Finger: Heretics, Activists and the Search for Justice in Science that describes how activists try to intimidate researchers when the activists disagree with the researchers’ work.

Roger Pielke Jr. reviews the book for Nature. From his blog, leading into his review, Roger describes why he empathizes with Dreger:

The Current Wisdom: The Short-Term Climate Trend Is Not Your Friend

The Current Wisdom is a series of monthly posts in which Senior Fellow Patrick J. Michaels reviews 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 Current Wisdom only comments on science appearing in the refereed, peer-reviewed literature, or that has been peer-screened prior to presentation at a scientific congress.


It seems like everyone, from exalted climate scientists to late-night amateur tweeters, can get a bit over-excited about short-term fluctuations, reading into them deep cosmic and political meaning, when they are likely the statistical hiccups of our mathematically surly atmosphere.

There’s been some major errors in forecasts of recent trends. Perhaps the most famous  were made by NASA’s James Hansen in 1988, who overestimated warming between then and now by a whopping 40% or so.

But it is easy to  get snookered by short-term fluctuations.  As shown in Figure 1, it is quite obvious that there has been virtually no net change in temperature since 1997, allowing for the fact that measurement errors in global average surface temperature are easily a tenth of a degree or more. (The magnitude of those errors will be considered in a future Current Wisdom).

Figure 1. Annual global average surface temperature anomaly (°C), 1997-2010 (data source: Hadley Center).

Some who are concerned about environmental regulation without good science have seized upon this 13-year stretch as “proof” that there is no such thing as global warming driven by carbon dioxide.  More on that at the end of this Wisdom.

Similarly, periods of seemingly rapid warming can prompt scientists to see changes where there aren’t any.

Consider a landmark paper published in 2000 in Geophysical Research Letters by Tom Karl, a prominent researcher who is the head of our National Climatic Data Center (NCDC) and who just finished a stint as President of the American Meteorological Society.  He couldn’t resist the climatic blip that was occurred prior  to the current stagnation of warming, namely the very warm episode of the late 1990s. 

Cooler heads at the time noted that it was an artifact of the great El Nino of 1997-98, a periodic warming of the tropical Pacific that has been coming and going for millions of years. 

Nonetheless, the paper was published and accompanied by a flashy press release titled “Global warming may be accelerating.”  

What Karl did was to examine the 16 consecutive months of record-high temperatures (beginning in May, 1997) and to calculate the chance that this could happen, given the fairly pokey warming rate—approximately 0.17°C (0.31°F) per  decade, that was occurring.  He concluded there was less than a five percent probability, unless the warming rate had suddenly increased.

From the press release:

Karl and colleagues conclude that there is only a small chance that the string of record high temperatures in 1997-98 was simply an unusual event, rather than a change point, the start of a new and faster ongoing trend.

He also gave a number:  “…the probability of observing the record temperatures is more likely with high average rates of warming, around 3°C [5.4°F]/century,” which works out to 0.3°C per decade.

Our Figure 2 shows what was probabilistically forecast beginning in May, 1997, and what actually happened.  Between then and now, according to this paper, global temperatures should have warmed around 0.4°C (0.7°F).  The observed warming rate for the last 13.5 years—which includes the dramatically warming temperatures beginning in 1997—was a paltry 0.06°C (0.11°F) per decade. 

Figure 2. Prior to mid-1997, the observed warming trend (dashed line) was 0.17°/decade.  Karl said there was a greater than 95% probability that 1997-8 would mark a “change point”, where warming would accelerate to around 0.30°/decade.  Since then, the rate has been 0.06°/decade, or 20% of what was forecast.

Karl did provide some statistical wiggle room.  While noting the less than 5% chance that the warming rate hadn’t increased, he wrote that “unusual events can occur” and that there still was a chance (given as less than 5%) that 97-98 was just a statistical hiccup, which it ultimately proved to be.

The press release couldn’t resist the “it’s worse than we thought” mindset that pervades climate science:

Since completing the research, the data for 1999 has been compiled.  The researchers found that 1999 was the fifth warmest year on record, although as a La Nina year it would normally be cooler” [than what?ed].

“La Nina” is cool phase of El Nino, which drops temperatures about as much as El Nino raises them. What the press release and the GRL paper completely neglected to mention is that the great warm year of 1998 was a result of the “natural”  El Nino superimposed upon the overall slight warming trend.

In other words, there was every reason to believe at that time that the anomalous temperatures were indeed a statistical blip resulting from a very high-amplitude version of a natural oscillation in the earth’s climate that occurred every few years.

Now, back to the last 13 years. The puny recent changes may also just be our atmosphere’s make-up call for the sudden warming of the late 1990s, or another hiccup.

It is characteristic for climate models whose carbon dioxide increase resembles that which is being observed to produce constant rates of warming.  There’s a good reason for this.  Temperature responds logarithmically—i.e.less and less—to changes in this gas as its concentration increases.  But the concentration tends to increase exponentially—i.e. more and more.  The combination of an increasingly damped response to an ever increasing rate of input tends to resemble a straight line, or a constant rate of warming.

Indeed, Karl noted in his paper (and I have noted in virtually every public lecture I give), that “projections of temperature change in the next [i.e. the 21st] century, using [the United Nations’] business as usual scenarios…have relatively constant rates of global temperature increase”.  It’s just that their constant rates tend to be higher than the one that is being observed.  The average rate of warming predicted for this century by the UN is about 2.5°C, while the observed value has been, as predicted, constant—but with a lower value of 1.7°.  As Figure 3 shows, this rate has been remarkably constant for over three decades.


Figure 3. Annual global average surface temperature anomaly (°C), 1976-2010 (data source: Hadley Center).  It’s hard to imagine a more constant trend, despite the 1998 peak and the subsequent torpid warming.

The bottom line is that short-term trends are not your friends when talking about long-term climate change.


Hansen, J.E., et al., 1988. Global climate changes as forecast by Goddard Institute for Space Studies three-dimensional model. Journal of Geophysical Research, 93, 9341-9364.

Karl, T. R., R. W. Knight, and B. Baker, 2000. The record breaking global temperatures of 1997 and 1998” Evidence for an increase in the rate of global warming? Geophysical Research Letters, 27, 719-722.

Michaels, P. J., and P. C. Knappenberger, 2009. Scientific Shortcomings in the EPA’s Endangerment Finding from Greenhouse Gases, Cato Journal, 29, 497-521, https://www.cato.org/pubs/journal/cj29n3/cj29n3-8.pdf.


UN Climate Official Steps In It, Then Aside

There are numerous possible reasons for UN climate chief Yvo de Boer’s decision to resign—from his inability to cobble together a new climate treaty last December in Copenhagen (where he wept on the podium), to recent revelations of his agency’s mishandling of climate change data.

What the climate science community and the public should focus on now are the ramifications of de Boer’s resignation.  For one thing, it signals that hope is dead for a UN-brokered global treaty that would have any meaningful effect on global temperatures.  It also means that the UN intends to keep its Intergovernmental Panel on Climate Change pretty much intact under the leadership of the scientifically compromised Rajenda Pauchari, who should have resigned along with de Boer.

This development guarantees that the Obama administration will have an unmitigated mess on its hands when signatories to the Framework Convention sit down in Mexico City this November in yet another meeting intended to produce a climate treaty.  The Mexico City meeting convenes six days after U.S. midterm elections, in which American voters are fully expected to rebuke Obama for policies including economy-crippling proposals to combat climate change.

In short, Mexico City is about as likely to produce substantive policy decisions as the TV show ‘The View.’  Backers of radical climate change measures are now paying the price for over two decades of telling the public—in this case literally—that the sky is falling.