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Climate Hustle

Explaining climate change science & rebutting global warming misinformation

Scientific skepticism is healthy. Scientists should always challenge themselves to improve their understanding. Yet this isn't what happens with climate change denial. Skeptics vigorously criticise any evidence that supports man-made global warming and yet embrace any argument, op-ed, blog or study that purports to refute global warming. This website gets skeptical about global warming skepticism. Do their arguments have any scientific basis? What does the peer reviewed scientific literature say?


Analysis: How much did El Niño boost global temperature in 2015?

Posted on 5 February 2016 by Guest Author

This is a re-post from Roz Pidcock at Carbon Brief

Almost as soon as the news broke that 2015 was the hottest year in the modern record, the conversation quickly turned to how much of the record-breaking warmth was down to climate change and how much to the Pacific weather phenomenon known as El Niño.

Carbon Brief has spoken to climate scientists working on this question, who all seem to agree El Niño was responsible for somewhere in the region of 10% of the record warmth in 2015.

But while the science seems pretty clear, these numbers got somewhat lost in the media coverage. So, too, did the fact that 2015 was far hotter than the last big El Niño year in 1997 – and that 2015 would still have been a record year even had the El Niño never occurred.

A wide margin

All three of the world’s major meteorological agencies came to the same conclusion last week. NASA, the US National Oceanic and Atmospheric Administration (NOAA) and the UK’s Met Office all confirmed 2015 was the warmest on record and the first year in which global temperature rose 1C above the preindustrial era.

Yesterday, the World Meteorological Organisation – which combines all three agencies’ data into a single definitive statement – agreed that 2015 was a record-breaking year.

As Carbon Brief and many others have noted, it isn’t so much the setting of a new record that is remarkable, but the margin by which 2015 took the top spot.

Combining the three global datasets, global temperature in 2015 was 0.16C above the next warmest year in 2014, a gap the WMO called “strikingly wide”.



Industrial-era ocean heat uptake has doubled since 1997

Posted on 4 February 2016 by Rob Painting

The oceans are by far the largest heat reservoir in the Earth's climate system, so much so that they make up a whopping 93% of global warming. Thus global warming is really the story of ocean warming. In many blog posts in recent years (see, here, here and here for example) Skeptical Science has consistently drawn attention to the fact that the oceans are continuing to accumulate heat and therefore, despite short-term fluctuations in both surface and atmospheric temperatures, global warming is proceeding largely as anticipated by the scientific community. 

A recent paper, Gleckler et al [2016], manages to put the recent warming of the ocean into a broader, longer-term, perspective. Using ocean temperature measurements obtained from various sources and methods, and utilizing data from the pioneering HMS Challenger expeditions of the late 19th century (Roemmich et al [2012]), the researchers were able to compare the observations stretching back to the mid-1800's with climate model simulations. They found the model simulations were consistent with this diverse collection of ocean temperature data. Perhaps the most startling result of this analysis is just how much the oceans have warmed in recent decades, with the recent acceleration so pronounced that the rate of ocean heat uptake in the industrial-era has doubled since 1997.

Figure 1 - The CMIP5 multi-model mean ocean heat content change from 1865 to 2015 expressed as a percentage for 3 ocean depth layers. The gray bars indicate the 1-standard deviation uncertainty and the black triangles along the bottom denote simulated large volcanic eruptions (which disperse light-scattering sulfate particles). Gray triangles show the many unsimulated small & moderate volcanic eruptions after 2000. Image from Gleckler et al (2016).

Adding greenhouse gases to the atmosphere makes the ocean warmer 

How additional greenhouse gases in the atmosphere cause the ocean to grow warmer is not generally well-known, so it's useful to provide some background context for this new research paper. In a similar vein to the warming of the atmosphere, the warming of the oceans occurs in response to the slowing of heat loss. It works like this: highly energetic solar (shortwave) radiation enters the surface layers and warms the ocean. The overlying air is typically cooler than the sea surface, so some ocean heat is lost to the atmosphere and any surplus is eventually radiated away to space high up in the atmosphere. The amount of heat in the ocean is therefore a balance between solar radiation entering the ocean and the energy which leaves it - mainly through evaporation. The oceans can warm through an increase in solar output (the sun has actually cooled in recent decades, thereby eliminating that as a potential cause) or by reducing the rate of heat loss to the atmosphere. This is where additional atmospheric greenhouse gases come in.



Measuring ocean heating is key to tracking global warming

Posted on 3 February 2016 by John Abraham

Human emissions of greenhouse gases such as carbon dioxide are causing the Earth to warm. We know this, and we have known about the heat-trapping nature of these gases for over 100 years. But scientists want to know how fast the Earth is warming and how much extra energy is being added to the climate because of human activities.

If you want to know about global warming and its future effects, you really need to answer these questions. Whether this year was hotter than last year or whether next year breaks a new record are merely one symptom of a warming world. Sure, we expect records to be broken, but they are not the most compelling evidence. 

The most compelling evidence we have that global warming is happening is that we can measure how much extra heat comes in to the Earth’s climate system each year. Think of it like a bank account. Money comes in and money goes out each month. At the end of the month, do you have more funds than at the beginning? That is the global warming analogy. Each year, do we have more or less energy in the system compared to the prior year? 

The answer to this question is clear, unassailable and unequivocal: the Earth is warming because the energy is increasing. We know this because the heat shows up in our measurements, mainly in the oceans. Indeed the oceans take up more than 92% of the extra heat. The rest goes into melting Arctic sea ice, land ice, and warming the land and atmosphere. Accordingly, to measure global warming, we have to measure ocean warming. Results for 2015 were recently published by Noaa and are available here.

A recent paper by Karina von Schuckmann and her colleagues appeared in Nature Climate Change, and provides an excellent summary of our knowledge of the energy balance of the Earth and recent advances that have been made. The article describes the complexity of the situation. The Earth is continuously gaining energy from greenhouse gases, but there are also natural fluctuations that cause both increases and decreases to the energy flows. 

For instance, volcanic eruptions may temporarily reflect some solar energy back to space. Natural variability like the El Niño/La Niña cycle can change heat flows and how deep the heat is buried in the ocean. The energy from the sun isn’t constant either; it varies on an 11-year cycle, but by less than 0.01%. With all of this and more happening, how do we know if an energy imbalance is natural or human caused? How do we separate these effects? 

The effort to separate human from natural effects is seen to be possible when one considers how the imbalance is measured in the first place. There are multiple complementary ways to make these measurements. Each technique has advantages and disadvantages and they have to be considered together.



'The Blob' Disrupts What We Think We Know About Climate Change, Oceans Scientist Says

Posted on 2 February 2016 by Guest Author

This is a re-post from DeSmog Canada

Deep in the northeast Pacific Ocean, The Blob is acting strangely.

When the abnormally warm patch of water first appeared in 2013, fascinated scientists watched disrupted weather patterns, from drought in California to almost snowless winters in Alaska and record cold winters in the northeast.

The anomalously warm water, with temperatures three degrees Centigrade above normal, was nicknamed The Blob by U.S climatologist Nick Bond. It stretched over one million square kilometres of the Gulf of Alaska — more than the surface area of B.C. and Alberta combined — stretching down 100-metres into the ocean.

And, over the next two years that patch of water radically affected marine life from herring to whales.

Without the welling-up of cold, nutrient-rich water, there was a dearth of krill, zooplankton and copepods that feed herring, salmon and other species.

The fish out there are malnourished, the whole ecosystem is malnourished,” said Richard Dewey, associate director for science with Ocean Networks Canada, speaking at Shaw Ocean Discovery Centre in Sidney on Thursday.

A change of three degrees is an “extraordinary deviation — something you would expect to happen once in a millennium,” he said.

Pink salmon returned last year, after two years in the ocean, weighing about half their usual weight, sea lion pups, seabirds and baleen whales had difficulty finding adequate food, but jellyfish thrived.

Now, after more than two years of disruption to marine ecosystems, it looks as if The Blob is dissipating, said Dewey, who has studied the phenomenon since it appeared.

Cold winter storms, that have been absent for almost three years allowing the anomaly to develop, swept across the Gulf of Alaska in November and December, finally dispersing the warm surface waters.

But, as oceanographers try to predict what will happen next, Dewey believes it is too early to pronounce the death of The Blob.

The Blob as captured in NOAA imaging in 2014. 

It’s not dead yet. I think there’s a lot of heat out there, deep down,” he said.



Fox News Republican debate moderators asked a climate question!

Posted on 1 February 2016 by dana1981

In the 2016 Republican presidential candidate debates, climate change has rarely been discussed. In last Thursday’s debate, the last before tonight’s Iowa caucus votes, on Fox News of all networks, there was one brief climate question directed at Senator Marco Rubio (R-FL). Unfortunately it was framed as a ‘gotcha, flip-flop’ question, with Rubio asked about his apparent support 8 years ago for a carbon cap and trade system in Florida, versus his current opposition to the concept.Rubio responded:

I have never supported cap and trade and I never thought it was a good idea. And I was clear about that at the time.

And I do not believe it’s a good idea now. I do not believe that we have to destroy our economy in order to protect our environment. And especially what these programs are asking us to pass that will do nothing to help the environment, but will be devastating for our economy.

When I am president of the United States of America, there will never be any cap-and-trade in the United States.

In another debate 4 months ago on CNN, Rubio made similar comments, adding:

America’s a lot of things, the greatest country in the world, but America is not a planet. And we are not even the largest carbon producer anymore, China is, and they are drilling a hole anywhere in the world that they can get ahold of.

Fact checking Marco Rubio

Politifact ruled it “mostly true” that Rubio never supported cap and trade. However, the rest of his comments are mostly false.



2016 SkS Weekly Digest #5

Posted on 31 January 2016 by John Hartz

SkS Highlights... El Niño Impacts... Toon of the Week... Quote of the Week... They Said What?... SkS in the News... SkS Spotlights... Coming Soon on SkS... Poster of the Week... SkS Week in Review... 97 Hours of Consensus...

SkS Highlights

Record hot 2015 gave us a glimpse at the future of global warming by Dana Nuccitelli (Climate Consensus - the 97%, The Guardian) garnered the highest number of comments of the articles posted on SkS during the past week. Climate scientists' open letter to the Wall Street Journal on its snow job by Emmanuel Vincent & Daniel Nethery (Climate Feedback) attracted the second highest number.

El Niño Impacts

Global temperatures will continue to soar over the next 12 months as rising levels of greenhouse gas emissions and El Niño combine to bring more record-breaking warmth to the planet.

According to the Met Office’s forecast for the next five years, 2016 is likely to be the warmest since records began. Then in 2017 there will be a dip as the effects of El Niño dissipate and there is some planet-wide cooling.

But after that, and for the remaining three years of the decade, the world will continue to experience even more warming. The forecast, which will be released this week, is the first such report that the Met Office has issued since it overhauled its near-term climate prediction system last year. 

Here is the weather forecast for the next five years: even hotter by Robin McKie, The Guardian, Jan 30. 2016

Severe El Niño-linked drought has destroyed crops, killed farm animals and dried up water sources across East Asia and the Pacific, aid workers said, and UNICEF appealed for $62 million to assist children impacted by various crises in the region.

Humanitarian agencies are monitoring and responding to droughts and food insecurity in an area from Indonesia and the Philippines, southeast to Papua New Guinea and the Pacific Islands.

"El Niño is peaking at the moment, and we expect the impacts to come up after the peak," said Krishna Krishnamurthy, a regional climate risk analyst for the World Food Programme.

El Niño parches Asia Pacific, destroying crops and drying up water sources by Alisa Tang, Thomson Reuters Foundation, Jan 26, 2016

Toon of the Week

 2016 Toon 5

Hat tip to I Heart Climate Scientists



2016 SkS Weekly News Roundup #5

Posted on 30 January 2016 by John Hartz

A chronological listing of the news articles posted on the Skeptical Science Facebook page during the past week.

Sun Jan 24



'If the world ends in 2100, we’re probably OK'

Posted on 29 January 2016 by howardlee

There’s a myopia in the climate discourse today.

“Everyone is focused on what happens by 2100. But that’s only 2 generations from today. It’s like: If the world ends in 2100 we’re probably OK!” says Professor Richard Zeebe of the University of Hawai’i. “But It’s very clear that over a longer timescale there will be much bigger changes.”

If the next century seems impossibly far off, bear in mind that if you have a young child now, we’re talking about the world her or his grandchildren will be trying to raise their kids in.

Scientists who take the long view on climate change see parallels between global warming today and mass extinctions in Earth’s past: “Apart from the stupid space rock hitting the Earth, most mass extinctions were CO2-driven global warming things,” says Professor Andy Ridgwell of Bristol University in the UK.

It has been a consistent pattern throughout geological time: “If you screw with the climate enough, you have huge extinctions,” says Ridgwell.

So much of what you read and hear about climate change is heavily based on instrument records that only go back 160 years or so. But Richard Zeebe and Andy Ridgwell are among a few scientists who look millions of years into Earth’s past to learn how the Earth responded to big additions of CO2 into the atmosphere before. I had the opportunity to chat with each of them about their work during the American Geophysical Union conference in San Francisco at the end of last year.

Beyond the ice ages

It’s true that scientists can learn about the ice age climate going back 800,000 years from bubbles of air trapped in ancient ice drilled from Greenland and Antarctica. They reveal many swings from warm to cold to warm again, in a low-CO2 world mostly cooler than today. “We went from very cold and low sea level to a mild climate with normal sea level,” says Ridgwell. But it was a very different scenario than today - those cycles were mainly driven by Earth’s wobbles as it circles the Sun, and those same orbital wobbles mean we should be cooling, not warming, today.

So both Ridgwell and Zeebe have been studying the best equivalent to modern climate change they have found so far, a relatively rapid global warming event that occurred 56 million years ago, called the “Paleocene-Eocene Thermal Maximum,” mercifully shortened to “PETM.” For Ridgwell, it’s a better analog for the future: 

This is why I like the PETM, at least it’s a warming event. It had a peak global warming of about 5º or 6ºC, which is a little bit beyond the end-of-the-century worst case scenario.

For Zeebe it’s also about data quality: 

We are focusing on the PETM is because we have relatively good sediment records. We are able to constrain timescales and ages relatively accurately. If you go further back in time, these constrains become very, very difficult.



Climate scientists' open letter to the Wall Street Journal on its snow job

Posted on 28 January 2016 by Guest Author

This is a guest post from Emmanuel Vincent and Daniel Nethery for Climate Feedback (@ClimateFdbk)

An opinion piece by Patrick Michaels in the Wall Street Journal (“The Climate Snow Job,” Jan. 24, 2016) is riddled with inaccuracies, according to an evaluation by ten scientists with relevant expertise.

The article makes false or misleading statements on several aspects of climate science, including the global temperature record, the methodology for measuring global temperature, the effect of El Niño on global temperature, and the economic impact of climate change. The mention of so many distinct aspects of climate science is intended to allow the author to pass himself off as an authority on climate science, while at the same time bamboozling readers into accepting three startlingly spurious claims.

Claim 1: “It is therefore probably prudent to cut by 50% the modelled temperature forecasts for the rest of this century.”

This is the opinion of the author with no basis in science. Climate models have successfully projected changes in climate observed in recent years. These models are not perfect representations of our climate system, but they are our best tool for forecasting future climate change.

Claim 2: “The notion that world-wide weather is becoming more extreme is just that: a notion, or a testable hypothesis.”

The scientific consensus is that some extreme weather events are becoming more severe and occurring with greater frequency in relation with climate change and more importantly these are expected to increasingly affect societies in the future. The author attempts to cast doubt on the science by claiming that the economic cost of extreme weather has remained stable over the past quarter-century. The author misleads the reader into concluding that because the economic cost of extreme weather has not increased, then extreme weather cannot have increased. But this fallacious reasoning is only the tip of the iceberg. Dr Laurens Bouwer, a senior risk analysis advisor at Deltares, told Climate Feedback that the claim that losses caused by severe weather have remained stable over the past 25 years is “not accurate”. It also belies the extent to which insurance agencies recognize the risks that climate change poses. The article cites data from Munich Re, whose head of Geo Risks Research and its Corporate Climate Centre, Professor Peter Höppe, has publicly stated that “climate change is one of the greatest risks facing humankind this century. Through a part of its core business, the insurance industry is directly affected and therefore assumes a leading role in devising solutions for climate protection and adaptation to the inevitable changes.”

Claim 3: “Without El Niño, temperatures in 2015 would have been typical of the post-1998 regime.”

This is false. Scientists estimate that the current El Niño event contributed only a few tenths of a degree to the record global temperature observed in 2015. The year would have gone down as the hottest on record even without the El Niño event, as explained in this article by The Carbon Brief.

Patrick J. Michaels would have his readers believe that the observed increase in global temperature, underlined by the news of the hottest year on record, is “business as usual”. His readers should instead draw the conclusion that no matter how conclusive the evidence, climate contrarians like Michaels intend to go about their “business as usual”, casting doubt on the science.



The science for climate change only feeds the denial: how do you beat that?

Posted on 27 January 2016 by John Cook

The ConversationAs the scientific consensus for climate change has strengthened over the past decade, the arguments against the science of climate change have been on the increase.

That’s the surprise finding of a study, published in the journal Global Environmental Change last month, which analysed and identified the key themes in more than 16,000 publications about climate change by conservative organisations.

Conservative think-tanks are organisations that oppose policies, such as regulation of pollution by the fossil fuel industry (some have also opposed regulation of the tobacco industry in the past and, in fact, some continue to do so today).

One study found that from 1972 to 2005, over 92% of climate contrarian books originated from conservative think-tanks. They are often ground zero for misinformation casting doubt on climate science, with their messages spread by contrarian blogs, conservative media and politicians opposing climate policy.



Study finds slim odds of record heat, but not as slim as reported

Posted on 27 January 2016 by John Abraham

No, this isn’t another article about how damn hot 2015 was. Although just between us, I may have lost a bet to climate seer Joe Romm because he correctly predicted 2015 would blow 2014 out of the water. Instead, this is a post about the probability that temperature records keep getting broken if climate change is natural.

A paper just published in Nature Scientific Reports by Michael Mann and Stefan Rahmstorf and their colleagues considered this question. In particular, they wanted to know how likely recent temperature records and the string of records would be if the climate was completely driven by natural variations. Not even including the crazy-hot 2015, what did the authors find?

Well it depended on the “record” they looked at. For instance, the likelihood that 13 of the hottest 15 years would be in the past 15 years is 1 in 10,000. The likelihood that 9 of the 10 hottest years occur in the past decade is 1 in 770. The results are similar regardless of whose temperature dataset is used.

Some media stories reported that the temperature records were even more unlikely. The reason this study arrived at different results is that they took into consideration the fact that temperature records are not like coin-flips. Each year is not independent of another year or the prevailing situation. 

For instance, there are natural events that alter the temperature such as volcanoes, variations in the solar output, or even internal variability such as the La Niña/El Niño cycle. If climate change were all natural, you could get these natural events to align just by chance, and this could give a naturally-occurring record. So, while it’s very unlikely that this could occur, it is much more likely than if we just treated each year as a coin flip.

The authors then asked how likely it would be to have a string of records given the reality of human-caused warming. They found that it’s 83% likely that 9 of the last 10 years would be the hottest on record and 76% likely that 13 of the past 15 years were hottest on record. They also found that the odds of 2014 being the hottest year on record was 40%. Without human influences, that chances 2014 would have been the hottest year is approximately 1 in a million. Mann said:

The press reports last year about the unlikely nature of recent global temperature records raised some very interesting questions, but the scientists quoted hadn’t done a rigorous calculation. As a result, the probabilities reported for observing the recent runs of record temperature by chance alone were far lower than what we suspected the true probabilities are.



Tracking the 2°C Limit - December 2015

Posted on 26 January 2016 by Rob Honeycutt

Holy frijole!

Okay, I'm not surprised that December beat November as the warmest anomaly in the entire GISS temperature record, but I was taken a little aback by how much. 

For a full size image click here.

One thing I note from this graph is the consistency between the peak (assuming we're likely near the peak of the surface warming due to the current super El Nino) and previous El Nino peaks in the GISS data. You essentially find the same trend as the trend in the full data set. Same follows for La Nina periods as well.

Many contrarians hold to the false notion that the current warming is "just" a function of the El Nino, whereas the current anomalies are clearly fully consistent with the long term rising trend is surface temperatures.

I'm also continuing to track the Ocean Nino Index (ONI) for this El Nino against the 1997/98 El Nino, and the ONI data is continuing on track. The ONI data goes all the way back to 1950 and the current 2.3 figure ties with 1997/98 as the highest in the entire data set. We will see next month if this El Nino breaks that record. Click here for a larger version of the graph below.



Record hot 2015 gave us a glimpse at the future of global warming

Posted on 25 January 2016 by dana1981

2015 smashed the record for hottest year by about 0.14°C. To put that into perspective, the previous two hottest years (2014 and 2010) only broke the prior records by 0.002°C, according to Berkeley Earth data. The only time the temperature record was shattered by such a large margin was in the monster El Niño year of 1998.

surface temp records

Various global surface temperature datasets, 1850–2015. Illustration: Zeke Hausfather

While the current El Niño event is also becoming monstrously strong, it’s only now reaching its peak intensity, and there’s an approximately 4-month lag before changes in El Niño are reflected in global surface temperature changes. Thus, the El Niño of 1998 had a greater warming influence than its 2015 counterpart. 2015 was nevertheless more than 0.2°C hotter than 1998, due to human-caused global warming.

As the animated graphic below shows, there’s a consistent warming trend among El Niño years, La Niña years, and neutral years. Over the past 50 years, there’s a 0.16°C per decade trend among each category, and individual years fall close to those trend lines. That underlying human-caused global warming trend is what’s causing annual temperatures to so frequently break records, with 4 new record-hot years in the past decade.

ENSO temps GIF

Berkeley Earth average global surface temperatures since 1965 categorized by type of El Niño year. Illustration: Dana Nuccitelli



2016 SkS Weekly Digest #4

Posted on 24 January 2016 by John Hartz

SkS Highlights... El Niño Impacts... Toon of the Week... Quote of the Week... He Said What?... SkS in the News... SkS Spotlights... Coming Soon on SkS... Poster of the Week... SkS Week in Review... 97 Hours of Consensus...

SkS Highlights

Ted Cruz fact check: which temperature data are the best? by Dana Nuccitelli (Climate Consensus - the 97%) garnered the highest number comments of the articles posted on SkS during the past week. The Little Ape That Could by Glenn Tamblyn attracted the second highest number of comments.

El Niño Impacts 

Toon of the Week

 2016 Toon 4

Hat tip to I Heart Climate Scientists



2016 SkS Weekly News Roundup #4

Posted on 23 January 2016 by John Hartz

A chronological listing of the news articles posted on the Skeptical Science Facebook page during the past week.

Sun Jan 17



Thorough, not thoroughly fabricated: The truth about global temperature data

Posted on 22 January 2016 by Guest Author

This is a re-post by Scott K. Johnson from Ars Technica

“In June, NOAA employees altered temperature data to get politically correct results.”

At least, that's what Congressman Lamar Smith (R-Tex.) alleged in a Washington Post letter to the editor last November. The op-ed was part of Smith's months-long campaign against NOAA climate scientists. Specifically, Smith was unhappy after an update to NOAA’s global surface temperature dataset slightly increased the short-term warming trend since 1998. And being a man of action, Smith proceeded to give an anti-climate change stump speech at the Heartland Institute conference, request access to NOAA's data (which was already publicly available), and subpoena NOAA scientists for their e-mails.

Smith isn't the only politician who questions NOAA's results and integrity. During a recent hearing of the Senate Subcommittee on Space, Science, and Competitiveness, Senator Ted Cruz (R-Tex.) leveled similar accusations against the entire scientific endeavor of tracking Earth’s temperature.

“I would note if you systematically add, adjust the numbers upwards for more recent temperatures, wouldn’t that, by definition, produce a dataset that proves your global warming theory is correct? And the more you add, the more warming you can find, and you don’t have to actually bother looking at what the thermometer says, you just add whatever number you want.”

There are entire blogs dedicated to uncovering the conspiracy to alter the globe's temperature. The premise is as follows—through supposed “adjustments,” nefarious scientists manipulate raw temperature measurements to create (or at least inflate) the warming trend. People who subscribe to such theories argue that the raw data is the true measurement; they treat the term “adjusted” like a synonym for “fudged.”

Peter Thorne, a scientist at Maynooth University in Ireland who has worked with all sorts of global temperature datasets over his career, disagrees. “Find me a scientist who’s involved in making measurements who says the original measurements are perfect, as are. It doesn’t exist,” he told Ars. “It’s beyond a doubt that we have to—have to—do some analysis. We can’t just take the data as a given.”

Speaking of data, the latest datasets are in and 2015 is (as expected) officially the hottest year on record. It's the first year to hit 1°C above levels of the late 1800s. And to upend the inevitable backlash that news will receive (*spoiler alert*), using all the raw data without performing any analysis would actually produce the appearance of more warming since the start of records in the late 1800s.

We're just taking the temperature—how hard can it be?

So how do scientists build datasets that track the temperature of the entire globe? That story is defined by problems. On land, our data comes from weather stations, and there’s a reason they are called weather stations rather than climate stations. They were built, operated, and maintained only to monitor daily weather, not to track gradual trends over decades. Lots of changes that can muck up the long-term record, like moving the weather station or swapping out its instruments, were made without hesitation in the past. Such actions simply didn’t matter for weather measurements.

The impacts of those changes are mixed in with the climate signal you’re after. And knowing that, it’s hard to argue that you shouldn’t work to remove the non-climatic factors. In fact, removing these sorts of background influences is a common task in science. As an incredibly simple example, chemists subtract the mass of the dish when measuring out material. For a more complicated one, we can look at water levels in groundwater wells. Automatic measurements are frequently collected using a pressure sensor suspended below the water level. Because the sensor feels changes in atmospheric pressure as well as water level, a second device near the top of the well just measures atmospheric pressure so daily weather changes can be subtracted out.

If you don't make these sorts of adjustments, you’d simply be stuck using a record you know is wrong.

Enlarge / A couple months of data from a groundwater well.  Scott K. Johnson



The Little Ape That Could

Posted on 21 January 2016 by Glenn Tamblyn

The little Ape that Could

(with apologies to Arnold Munk)


A couple of years ago, on a panel TV show about climate change on the BBC, an audience member commented that they thought the idea that humanity could influence something like the earth's climate was arrogant. There is an important insight here if we unpack this thought a little.

Is it arrogant to think we should seek to influence the climate? Yes, possibly, depending on your point of view. But that wasn't their point I think. Their point was that thinking we could influence the climate is arrogant. But it isn't arrogant; neither is it humble.

It is a measurement.

How powerful does 'something' have to be to influence the climate? And how powerful are we now? Both of these are questions that we can estimate quantitative answers to.

The simple fact is, that over my lifetime - I was born in 1957 - or somewhat longer, humanity's power has grown enormously, and we haven't really noticed. This has been called the Great Acceleration and it has happened in one lifetime.

So lets look at some measurements, some data on just how powerful we have become.


More People.

For most of human history the world's population was less than one billion people. In the time of Christ it was perhaps 200-300 million. We only reached one billion around 1800, two billion around 1925, three billion around 1960. We have added a billion people every 14 years or so since then.


"Population curve" by El T - originally uploaded to en.wikipedia as Population curve.svg. The data is from the "lower" estimates at


For a child born after the end of WWII, the world's population tripled in their lifetime. This has never ever happened to any other generation before them in all of history, and is unlikely to ever happen again. They, we, are a unique generation in history.



A striking resemblance between testimony for Peabody Coal and for Ted Cruz

Posted on 20 January 2016 by John Abraham

In a recent congressional hearing, Ted Cruz (one of the leading candidates for the Republican presidential nomination) first asked us to follow the science, and then misused and abused the very science he reportedly admires. The contrarian scientists that were invited to testify are members of a shrinking tribe that every year has to work harder to deny the clear evidence of a human-caused warming world.

Those scientists were William HapperJudith Curry, and John Christy. They argued that the Earth isn’t warming (or has slowed its warming) or that satellite temperature measurements are the best way to measure the Earth’s temperatures. In fact, satellites don’t measure temperature at all, but these witnesses didn’t mention that fact. 

Additionally, the satellite measurements that they showed are from the middle of the troposphere, high in the atmosphere (not at the surface). Finally, the contrarians declined to emphasize that the synthetic satellite temperature data have been wrong for years. The upper part of the atmosphere (stratosphere) is cooling as a result of the increased greenhouse gases while the lower layer (the troposphere) is warming. If any measurements of the stratosphere bleed into the measurements of the troposphere, it can cause a cooling bias.

I had the (dis)pleasure of testifying at a hearing in Minnesota where William Happer also testified. He, Roy Spencer, and Richard Lindzen all made errors in their testimony that were repeated at the Cruz congressional hearing. At the Minnesota hearing, these contrarians were representing Peabody Energy – the world’s largest private sector coal company.

They focused on high-altitude temperatures in the tropical part of the globe (near the equator) rather than temperatures at the surface or in the oceans. But it gets even worse – they combined two sets of satellite data into a single curve when in reality, satellite temperature measurements differ by as much as a factor of four depending on whose data you use! 



A Rough Guide to Rainfall, Run-off and Rivers

Posted on 19 January 2016 by John Mason

Introduction: a moment of realisation. July 2001, North Wales, UK

Pulling onto the side of the forestry road the air was thick with a single smell – that of mangled conifer wood. I locked the Land Rover and scrambled down to the river. It was a familiar route, an anglers' path that weaves its way cunningly for several tens of metres through steep, dense undergrowth. But something was different this time. The vegetation ended abruptly some way before it should have done. Where there had been soil, grass, rhododendron and bramble, naked rock now gleamed in the sunshine. Continuing down, I saw that the river, back down to its normal level, had an unusually clouded, milky look to it. Upstream was a prominent bluff of rock, several metres higher than its surroundings, on top of which a large Douglas Fir tree stood. It was still there, but the first few metres of its trunk were thickly and tightly wrapped with branches and tree trunks, their bark stripped away. Scrambling up the tight cone of flood-borne debris, I turned and looked down. It was at least ten metres from the top of the debris-wrap down to the water.

July 2001, North Wales

above: aftermath of a huge flash flood in July 2001, Afon Mawddach, North Wales. The figure perched on the left-hand side of the debris-wrap is a good 2 metres tall. Photo: author.

Two days before, a severe thunderstorm had affected the region. Had the area been well-populated, the resulting flash floods would have made the national headlines. Houses would not just have been flooded: some would have been swept away. It served, in the author's case, to raise an awe-struck awareness of just what can happen when the required meteorological ingredients come together. You cannot beat seeing things for yourself.

Why a rainfall primer?

So: what makes the difference between an ordinary wet day and an extreme rainfall? Judging by the often confused and contradictory comments from online discussions in the wake of the late 2015 floods, this seems as good a time as any for a primer - the three R's of flooding if you like. Rainfall, run-off and rivers. It is aimed primarily at UK readers and a lot of the illustrated examples are from Wales, because that's where I live and they are things that I have seen for myself, but the same principles apply in many parts of the world, outside of the Tropics. Rainfalls in extratropical parts of the world have a complex set of causative factors and effects. This post takes a more detailed look at both. It is by necessity long, because you cannot realistically deal with complex topics in a few soundbites, so it has been divided into sections, linked to by the seven bookmarks below.



Ted Cruz fact check: which temperature data are the best?

Posted on 18 January 2016 by dana1981

The information in this post has been incorporated into the new rebuttal to the myth 'satellite [temperature] data are the best data that we have,' available at

Satellites don’t measure the Earth’s temperature. Senator Ted Cruz (R-TX) and his fellow climate contrarians love the satellite data, but as Carl Mears of the Remote Sensing Systems (RSS) satellite dataset and Ben Santer recently wrote,

they are not thermometers in space. The satellite [temperature] data ... were obtained from so-called Microwave Sounding Units (MSUs), which measure the microwave emissions of oxygen molecules from broad atmospheric layers. Converting this information to estimates of temperature trends has substantial uncertainties.

Scientists process the raw microwave data, applying a model to make numerous adjustments in order to come up with a synthetic estimate of the atmospheric temperature. Climate scientists have identified many errors in the model, and so it’s undergone several major revisions. It’s a complicated process for many reasons discussed in greater detail in this new Skeptical Science myth rebuttal, and by Mears and Santer

For example, satellites have a limited lifetime and are replaced (so far there have been 10 different satellites with MSUs); the MSU instruments change - they now use advanced MSUs (AMSUs); their orbits drift and decay due to friction; clouds get in the way; they have to isolate the data from the different layers of the atmosphere, etc.

In a recent Senate hearing, Ted Cruz and one of his witnesses, Judith Curry, claimed “the satellite data are the best data we have.” Most experts disagree.

 Video by Peter Sinclair for Yale Climate Connections.

What makes “the best” the best?

At first blush the claim sounds plausible. After all, satellites are high tech! But how do we decide which data are “the best”? That’s a subjective question, but we can apply some objective criteria to answer it.

For example, as humans, we might consider the temperature where we live (at the Earth’s surface) the most important. Satellites estimate the temperature of the atmosphere, most of which is above us. In fact, as John Christy, who runs the University of Alabama at Huntsville (UAH) satellite dataset recently said,



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