Climate deniers' excuses falling apart

A new study suggests that the University of Alabama at Huntsville is lowballing the warming of the atmosphere

John Abraham

Wednesday 25 March 2015 13.00 GMT Last modified on Wednesday 25 March 2015 13.03 GMT

A very important study was just published in the Journal of Climate a few days ago. This paper, in my mind, makes a major step toward reconciling differences in satellite temperature records of the mid-troposphere region. As before, it is found that the scientists (and politicians) who have cast doubt on global warming in the past are shown to be outliers because of bias in their results.

The publication, authored by Stephen Po-Chedley and colleagues from the University of Washington, discusses some major sources of error in satellite records. For instance, after satellites are launched, they scan the Earth’s atmosphere and calibrate the atmospheric measurements using a warm target onboard the satellite and cold space. The accuracy with which the atmospheric measurements are calibrated can influence the inferred temperature of the atmosphere (called the warm-target bias). Additionally, over the years, multiple satellites have been launched and the selection of which satellite data are used can play a role. Finally, biases can occur because the satellite orbits drift during their lifetime and the influence of diurnal temperature variation can affect the global temperature trends.

Of these three errors, the last one (probably the most important one), was the focus of the just-published paper.

It is known that there is a problem because there are multiple groups that create satellite temperature records. For instance, NOAA, Remote Sensing Systems (RSS), and the University of Alabama Huntsville (UAH). The problem is, their results don’t agree with each other. In particular, the UAH team, led by Dr. John Christy and Dr. Roy Spencer (who have discounted the importance and occurrence of climate change for years) present results that differ quite a bit from the others. In fact, in the current paper, it is stated that “Despite using the same basic radiometer measurements, tropical TMT trend differences between these groups differ by a factor of three.”

An important aspect to this issue is that for many reasons, it is expected that the tropospheric temperatures in the tropics will warm more than surface temperatures. This is called “tropospheric amplification.” According to two satellite groups, there is in fact such amplification. According to the UAH team, there is no amplification. The presence or absence of amplification is often used by some skeptics to discount the importance of global warming.

Why are there differences? Well that’s part of what this paper tries to answer.

Each of the teams try to deal with and correct for various satellite errors. For instance, sometimes the diurnal cycle effect is removed using temperatures from climate models. The RSS and NOAA teams “apply a drift correction based on the diurnal cycle from a GCM (global climate model) whereas UAH produces a microwave sounding unit mid-tropospheric temperature diurnal correction based on temperature comparisons between three co-orbiting satellites ... UAH does not yet correct the diurnal drift for satellites carrying Advanced Microwave Sounding Units because they attempt to use these satellites during periods when the diurnal drift is small.”

The present paper presents a calibration scheme that allowed them to obtain a diurnal correction from the satellite measurements themselves, in particular, by solving for a common diurnal cycle correction using temperatures from all available satellites.

As the authors state in the paper, their new results agree with the two groups that show more warming. They disagree with UAH. As the authors state,

In general, our trends corrected with a GCM and trends corrected with our observationally derived diurnal cycle correction are similar to trends from NOAA and RSS ... the UAH ocean trend is notably lower than trends from the other datasets.

So, how do the trends compare? Well the lowest trend, in degrees Celsius heating per decade are from UAH and they equal 0.029 for the 1979–2012 period for the mid-troposphere region between 20° South and 20° North. The new results are almost 4 times higher at 0.114°C per decade. The results using a diurnal correction from a climate model are in close agreement with the new findings (0.124°C per decade). As additional support, the NOAA and RSS values are also close to the corrected results. The simple fact is, UAH is an outlier.

They also discovered that the results from RSS, NOAA, and the new study all show tropical amplification and are in agreement with the expected amplification from climate models. They state, “There is no significant discrepancy between observations and models for lapse rate change between the surface and the full troposphere.”

To summarize the amplification factor, the new study obtains a value of 1.4. If the diurnal cycle is eliminated using climate models, the result is 1.49. According to NOAA and RSS, the values are 1.31 and 1.10, respectively. Again, UAH is the outlier with an amplification factor of 0.56.

I wrote to Stephen Po-Chedley and asked for a summary. He told me,

We developed an observationally based diurnal cycle correction to remove the influence of satellite diurnal sampling drifts on long-term tropospheric temperature trends. This is important because other analyses (RSS and NOAA) used a model-derived diurnal cycle correction and questions have been raised about the validity of this bias correction. Trends from our work are in accord with trends from global circulation models and basic theory.

We also found that the model-derived diurnal cycle correction used by RSS and NOAA is similar to our bias correction. The tropical tropospheric trend from the present study is 2.5 times that from another group, UAH. While this work shows that it is possible to understand discrepancies between MSU/AMSU datasets there are still important differences between the datasets that need further scrutiny.

In short, the Earth is warming, the warming is amplified in the troposphere, and those who claim otherwise are unlikely to be correct.

John Christy and Roy Spencer are pro-fossil fuel and anti-scientific consensus

Dana Nuccitelli

Monday 6 April 2015 14.00 BST Last modified on Monday 6 April 2015 15.14 BST

In 1990, University of Alabama at Huntsville scientists Roy Spencer and John Christy created a data set that estimates the temperature of the Earth’s atmosphere by using instruments on satellites (microwave sounding units) that measure microwave radiation in the atmosphere. According to their latest estimates, the Earth’s lower atmosphere has warmed significantly since satellite measurements began in 1979, but not quite as fast as thermometer measurements of temperatures at the Earth’s surface.

Spencer and Christy have also long disputed the degree to which humans are contributing to that warming, and have thus often been called to testify before Congress by policymakers seeking justification to oppose climate legislation. On the 25th anniversary of their satellite data set, Alabama.com interviewed the pair to discuss their science and climate contrarianism. The resulting discussion was quite revealing.

Consensus Denial

For example, when asked about the 97% expert consensus on human-caused global warming, Christy offered an inaccurate response,

The American Meteorological Society did their survey and they specifically asked the question, Is man the dominate controller of climate over the last 50 years? Only 52 percent said yes. That is not a consensus at all in science ... Roy and I have both made the statement that we are in the 97 percent because we believe in some (man-made) effect.

Ever since my colleagues and I published our global warming consensus paper two years ago in which we found a 97% consensus in the peer-reviewed literature on human-caused global warming, Roy Spencer has been claiming to be part of the 97%. As I showed two years ago, he’s not. Spencer and Christy each authored five papers captured in our climate science literature survey. Among those papers, we classified one of Spencer’s and two of Christy’s as minimizing or rejecting the human influence on global warming, and the others as not taking a position on the issue.

That makes both of them authors of the less than 3% of peer-reviewed climate science papers rejecting the consensus on human-caused global warming. This is an indisputable fact – the 97% consensus figure is based on our team’s categorization of the scientific literature, and we put their research outside the 97% consensus. Spencer and Christy reject this fact because they don’t understand our study – specifically that papers minimizing the human influence on global warming fall outside the 97% consensus. Their research is nevertheless among the 3% of outliers.

As for the American Meteorological Society (AMS) survey, only 13% of participants described climate science as their field of expertise. The Heartland Institute – the source of the story linked in the above quote by Christy – misrepresented the associated study so badly that the AMS executive director took the unusual step of issuing a public reprimand against their behavior. Studies of climate science experts have again and again found a 97% consensus on human-caused global warming.

Data and Research Quality

Spencer and Christy’s data set has undergone many major corrections to address various errors and biases. This is how science always progresses, but those who believe that adjustments to surface temperature measurements are part of a conspiracy (including Roy Spencer) always seem to neglect the major adjustments to the satellite data. In fact, in its early days, Spencer and Christy’s data set seemed to indicate the atmosphere was cooling, before a series of big adjustments were made.

As discussed in my book and as a paper that John Abraham and I published with several colleagues last year showed, much of Spencer and Christy’s contrarian research has not withstood subsequent scientific scrutiny.

we conclude then that the quality of work of contrarian-view scientists, as showcased here by representative case studies, is notably lower than that of scientists who hold the consensus view ... We find that the scientific literature includes a series of strong responses from the mainstream scientific community including criticisms, corrections, and in some cases, resignation of editors. The contrarian views were often found to be unsubstantiated by the data and are no longer seriously considered by many climate scientists.

In fact, the accuracy of Spencer and Christy’s atmospheric temperature estimates remains a question of rigorous scientific dispute today. While the Alabama.com interview says,

Still, they carry on - comfortable in their research and data that has remained true to their findings

That comfort may very well be misplaced.

Conspiracies and Biases

When asked about data from government agencies contradicting their contrarian beliefs about the dangers associated with climate change, Christy said,

NASA, NOAA, EPA, DOE, those are agencies. Agency leaders are appointed by the government, by the current administration. They do not represent objective independent scientific organizations. They can’t. They are appointed by the head. They try. People who come out with different views in their organizations are found to be squashed. There is an agenda in those agencies ... There are skeptics in NASA and NOAA, a good number. But they are quiet. They know in this administration, they don’t speak out.

This is an ironic answer given the recent revelations that scientists in Florida have been barred from using phrases like “climate change” and “global warming.” Similarly, the George W. Bush administration was accused of censoring government reports about climate change. It’s contrarians who have tried to squash inconvenient scientific research, not those who accept the scientific consensus on human-caused global warming.

Fossil Fuel Interests

The interview also included an extensive discussion about fossil fuels, with Roy Spencer saying,

When I talk to scientists who should be objective over a beer at the end of the day, I will argue with them and their final position will always be, ‘Yeah, but we need to get away from fossil fuels anyway.’ Where did that come from? Are you an expert in alternative energy sources and what they cost? How many poor people are you going to hurt? How many more people are you going to make poor through energy poverty because they are paying five to 10 times as much for their energy?

Roy Spencer is of course not an energy or economics expert either. Experts in these fields who have published research on the subject have found that fossil fuels are incredibly expensive, when we account for all of their costs. For example, one recent study conservatively estimated that including pollution costs, coal is about 4 times more expensive than wind and 3 times more expensive than solar energy in the USA today. Additionally, poorer countries are generally the most vulnerable to climate change impacts. John Christy made similarly backwards arguments,

Carbon dioxide makes things grow. The world used to have five times as much carbon dioxide as it does now. Plants love this stuff. It creates more food. CO2 is not the problem ... There is absolutely no question that carbon energy provides with longer and better lives. There is no question about that.

The ‘CO2 is plant food’ argument is a gross oversimplification. For example, rising carbon dioxide levels increase the greenhouse effect, causing global warming, which in turn intensifies droughts. As we’re seeing in California right now (the Golden State turning brown), that’s not good for plants.

Christy also made a key mistake in those comments. Energy gives people longer and better lives, but there’s absolutely no reason that energy must come from carbon-intensive fossil fuel sources. In fact, my colleague John Abraham is helping developing countries in Africa deploy clean energy sources instead.

Christy and Spencer have also been affiliated with various conservative fossil fuel-funded think tanks. And Spencer is on the Board of Advisors of the Cornwall Alliance – a religious group that essentially believes God wouldn’t let damaging climate change happen. Spencer has also made some controversial comments, calling those who disagree with him “global warming Nazis” as well as declaring “I love FoxNews” and saying,

I view my job a little like a legislator, supported by the taxpayer, to protect the interests of the taxpayer and to minimize the role of government.

Well, not really. As we’re about to see, this is a claim that dissolves on contact with actual science. But that didn’t stop the press from running with it.

If you follow the link I gave to the New York Times piece, you will see that this opening sentence has since been rewritten, for reasons which will soon become clear. But the Times wasn’t the only paper to start with that claim, and most of the headlines are still up. The Washington Post has: “2014 Was the Hottest Year in Recorded History.” The Boston Globe: “2014 Was Earth’s Hottest Year in Recorded History.” And so on.

You can see how misleading this is. When you read the phrase “in recorded history,” you think we’re talking about a really long time—the time dating back to the first historical records in Sumeria, circa 3500 BC. (That’s what you’ll find if you look up the phrase “recorded history.”) That’s a time frame of 5,000 to 6,000 years. But in the case of the temperature record, it actually means only 135 years. Accurate, systematic, global thermometer measurements of surface temperatures go back only to 1880. That’s why the Times report, presumably after getting whacked for a wildly misleading opening sentence, changed it to: “Last year was the hottest on earth since record-keeping began in 1880.” Which is a whole lot less impressive.

That “recorded history” gaffe is even worse when you consider that during “recorded history,” in the 5,000-year sense of the phrase, there’s good evidence that the Earth has been warmer than it is today.

We don’t have thermometer measurements going back that far, but scientists can use “proxies”—things they can measure that tend to vary with temperature, such as the composition of ancient deposits of seashells, or the thickness of the rings in ancient, slow-growing trees—to get very rough estimates. These have usually shown warmer temperatures during Roman times and the Middle Ages, when “recorded history” describes wine grapes growing in Northern England and Newfoundland.

There have been a few attempts to write these warm periods out of existence—one of them being Michael Mann’s infamous “hockey stick” graph, which implausibly asserts that global temperatures remained totally flat in every century except the 20th—but these claims have been controversial to say the least.

That’s why the implication that this is the warmest year ever in all of human history should never have gotten by a reporter who knows the first thing about the science on this issue. It implies a claim that we’re pretty sure just isn’t true.

Now let’s move on to the corrected statement, that this is the hottest year since the thermometer record began in 1880. But this a very short time for gathering data about the climate and distinguishing new trends from natural variation. For example, about half of the warming that occurs in that time happens prior to 1940, before it could have been caused by human activity. This warming was probably a natural rebound from the Little Ice Age, a cool period that ended in the middle of the 19th century.

More broadly, all changes in temperature that we observe today are relatively small variations within a much larger trend on a geological time scale. We know that the earth is going through a series of freezing and warming cycles on a scale of tens of thousands to hundreds of thousands of years. And it has mostly been freezing. We’re fortunate enough to live in a cozy, warm “interglacial” period between ice ages. So we’re all staring down the barrel of the next ice age, yet we’re spending our time worrying about global warming.

But let’s say we take this hyperventilation about a few relatively warm decades seriously. Even by that standard, this latest claim is ridiculously over-hyped.

If 2014 is supposed to be “hotter” than previous years, it’s important to ask: by how much?

You can spend a long time searching through press reports to get an actual number on this—which is a scandal unto itself. Just saying one year was “hotter” or “the hottest” is a vague qualitative description. It isn’t science. Science runs on numbers. You haven’t said anything that is scientifically meaningful until you state how much warmer this year was compared to previous years—and until you give the margin of error of that measurement.

The original NASA press release did not give those figures—and most press reports just ran with it anyway. This in itself says a lot. When it comes to global warming, “journalism” has come to mean: “copying press releases from government agencies.”

But a few folks decided to do some actual journalism, and Britain’s Daily Mail reports that

the NASA press release failed to mention…that the alleged ‘record’ amounted to an increase over 2010, the previous ‘warmest year’, of just two-hundredths of a degree—or 0.02C. The margin of error is said by scientists to be approximately 0.1C—several times as much.

Pause for a moment to digest that. The margin of error was plus or minus one tenth of a degree. The difference supposedly being measured here is two hundredths of a degree—five times smaller than the margin of error. The Daily Mail continues:

As a result, GISS’s director Gavin Schmidt has now admitted NASA thinks the likelihood that 2014 was the warmest year since 1880 is just 38 per cent. However, when asked by this newspaper whether he regretted that the news release did not mention this, he did not respond.

This is not exactly a high point in the employment of the scientific method.

If we take into account this margin of error, the most we can say is that 2014 was, so far as we know, just as warm as 2005 and 2010. There is no significant difference between these years. And that gives the lie to claims of runaway global warming. As the redoubtable Judith Curry recently pointed out:

The real issue that is of concern to me is the growing divergence between the observed global temperature anomalies and what was predicted by climate models. Even if 2014 is somehow unambiguously the warmest year on record, this won’t do much to alleviate the growing discrepancy between climate model predictions and the observations.

She links to this graph which shows that observed temperatures are falling at or below the low end of the range predicted by the climate models. With every year that passes, the models predict a greater and greater increase in temperature—but the actual observations remain stubbornly flat. Curry concludes that “ranking 1998, 2005, 2010, and 2014 as the ‘warmest years’ seems very consistent with a plateau in surface temperatures since 1998.”

So allow me to suggest a more accurate first sentence to sum up this story: “In the tiny little blip of geological time for which we have accurate surface temperature records, last year was pretty much the same as 2005 and 2010, continuing a plateau of global temperatures that has lasted nearly 20 years.”

What remains of the original description of this news? Nothing but bluff, spin, and the uncritical press-release journalism that dominates mainstream reporting on the climate. It may or may not be the hottest year ever, but this is definitely in the running for the most dishonest year on record.

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A team of researchers led by Jamin Greenbaum of the University of Texas at Austin has discovered two seafloor troughs that could allow warm ocean water to reach the base of Totten Glacier, East Antarctica’s largest and most rapidly thinning glacier. The discovery probably explains the glacier’s extreme thinning and raises concerns about how it will affect sea level rise.

The Totten Glacier catchment, outlined in blue, is a collection basin for ice and snow that flows through the glacier. It’s estimated to contain enough material to raise sea levels by at least 3.5 m. Image credit: Jamin Greenbaum / Australian Antarctic Division.