2010: A Year of Record Warmth and Weird Weather

Last year’s global temperatures are in, and the result is that 2010 is statistically tied with 2005 for the title of the warmest year since records began in 1880.

According to the US National Oceanic and Atmospheric Administration’s National Climatic Data Center (NOAA NCDC), the global temperature for both years was 0.62°C above the 20th-century average 13.9°C; 2010 came second by a thousandth of a degree. (Climatologists usually give temperatures as anomalies relative to an average, because they are easier to compare than absolute temperatures. The last month with a temperature below average was February 1985.)

2010 set new records for the warmest March, April, May, and June. Indeed, when the seasonal cycle is removed March 2010 was the third warmest month of all time (April, May, and November 2010 were also among the top 20). The ten warmest years according to NCDC are 2005/2010, 1998, 2003/2002, 2006/2009, 2007, 2004, and 2001. The 15 warmest years have all occurred since 1995; every year since 1976 has been above average. The 2000s are the warmest decade on record, followed by the 1990s and 1980s.

2010 was the Northern Hemisphere’s warmest year and the Southern Hemisphere’s sixth warmest. The former had its warmest April, May, June, July, August, and November in 2010, while the latter had its warmest February. There was particularly strong warmth in Greenland, Canada, northern Africa, and the Middle East; as well as warmer than average temperatures in southern Africa, eastern Europe, eastern Russia, and southern Asia; and cooler than average temperatures in central Russia and northern Europe. Except for the eastern Pacific, most of the oceans were warmer than average; the North Atlantic was particularly warm.

Source: NOAA National Climatic Data Center

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Monckton Myth: Global Sea Ice

I wrote this post for Skeptical Science as part of an ongoing series looking at the arguments made by Christopher Monckton against climate science.

This post examines Monckton’s arguments about global sea ice. Monckton claims:

[T]he global sea ice record shows virtually no change throughout the past 30 years, because the quite rapid loss of Arctic sea ice since the satellites were watching has been matched by a near-equally rapid gain of Antarctic sea ice.

Global Sea Ice Is Decreasing

Have Arctic ice losses truly been balanced by Antarctic gains? The first point to clarify is that we are talking about floating sea ice, not to be confused with land ice. Land ice at both poles and in glaciers around the world is sliding into the ocean at an accelerating rate. This net loss of land ice is contributing to sea level rise.

However, Monckton is clearly referring to sea ice. The rapid decline of Arctic sea ice has indeed coincided with an increase in Antarctic sea ice. But do these two opposite trends cancel out as Monckton suggests? In reality, the upward Antarctic trend is only slight compared to the plummeting Arctic trend. Tamino has crunched the numbers and found the Arctic trend is in fact more than three times faster than the Antarctic one. The net result is a statistically significant global decrease of more than a million km2 – would you agree with Monckton that this is “virtually no change”?

Figure 1: Global sea ice extent since 1979. (Image source: Tamino. Data is from US National Snow and Ice Data Center.) Continue reading

Scientific Guide to Global Warming Skepticism

The Skeptical Science team (which includes myself) have recently completed a 16-page booklet called The Scientific Guide to Global Warming Skepticism. (Actually it was completed a fortnight ago, but I forgot to link to it at the time. Anyway, better late than never.)

To quote John Cook’s blog post launching the Guide:

Scientific skepticism is healthy. In fact, science by its very nature is skeptical. Genuine skepticism means considering the full body of evidence before coming to a conclusion. However, when you take a close look at arguments expressing climate ‘skepticism’, what you often observe is cherry picking of pieces of evidence while rejecting any data that don’t fit the desired picture. This isn’t skepticism. It is ignoring facts and the science.

The Scientific Guide to Global Warming Skepticism looks at both the evidence that human activity is causing global warming and the ways that climate ‘skeptic’ arguments can mislead by presenting only small pieces of the puzzle rather than the full picture.

The Guide explains the science in brief, plain language without getting too technical. For those who wish to dig deeper into the science, more detailed treatments can be found at the following pages (often presented with varying levels of complexity from Basic to Advanced):

The Fake Scandal of Climategate

This post was written for Skeptical Science as the first part of a series on the fake scandal of Climategate.

It’s bad enough that global warming contrarians are successfully misleading the public by propagating misconceptions about climate science. But recently it has become popular to attack climate scientists themselves, to accuse them of fraud and conspiracy. Exhibit No. 1 of the climate conspiracy theory is a collection of emails stolen (or possibly leaked) from the Climatic Research Unit (CRU) of the University of East Anglia (UEA), which appeared on the internet in November 2009.

Founded in 1972, CRU is only a small research unit with around 16 staff. CRU is best known for its work, since 1978, on a global record of instrumental temperature measurements from 1850 to the present, or CRUTEM. CRU’s land surface temperatures are combined with the UK Met Office Hadley Centre’s sea surface temperatures to form the global land-ocean record HadCRUT. CRU has also published reconstructions of pre-1850 temperatures based on tree rings, and CRU scientists have been involved in the Intergovernmental Panel on Climate Change (IPCC).

The 1,073 emails span 13 years of correspondence between colleagues at CRU. Much of it is mundane, but in this digital age it took only a matter of hours for contrarians to do some quote-mining. Contrarians alleged that the CRU scientists had manipulated data to support predetermined conclusions, that they had stonewalled Freedom of Information (FoI) requests for data, and that they had corrupted the peer review and IPCC processes.

The story was quickly dubbed “Climategate”, and it spread rapidly from arcane contrarian blogs through conservative columnists to the mainstream media. The hyperbole was turned up to eleven. Conspiracy theorists had a field day, claiming that anyone even mentioned in the emails, or remotely connected to CRU, must also be part of a conspiracy. In this way, the Climategate conspiracy theory snowballed to include the entire field of climate science. The Climategate emails were held up as “the final nail in the coffin of anthropogenic global warming”, and the media were only too happy to play up the controversy.

The CRU scientists have been cleared

In the months that followed, there were several inquiries into the allegations resulting from the emails. When a few of the more suggestive email quotes are reeled off by pundits without much context, they can sound pretty damning. But each and every one of these inquiries has found no fraud and no conspiracy. Continue reading

2010 Temperature Update: Earth’s Second Warmest 12 Months on Record

NOAA’s National Climatic Data Center (NCDC) have just updated their global surface temperature anomalies to include this September, so I thought it was time I updated my 2010 temperatures page, which was becoming rather neglected.

To recap, the year began with an unusually cold winter in northern land areas which had a disproportionate impact on public opinion. Yet while conservative commentators chattered about the cold winter, the global temperature soared. Globally January 2010 was a relatively warm month, and February 2010 was the warmest February on record in the Southern Hemisphere. March 2010 was not only the warmest March globally, but also the third warmest month of all time (seasonally adjusted), after February 1998 and January 2007. April 2010, May 2010, and June 2010 were the warmest April, May, and June respectively.

As predicted, during July 2010 the El Niño Southern Oscillation (ENSO) shifted to a La Niña phase, causing global temperatures to begin dropping. Nevertheless, it was still the second warmest July on record (after July 1998), at 0.66°C above the July average of 15.8°C. (Climatologists usually give temperatures as anomalies, in NCDC’s case anomalies relative to a 20th century average, because they are easier to compare than absolute temperatures.) In the Northern Hemisphere, it was the warmest July, with the warmest temperature anomalies in Europe, western Russia, eastern Asia, eastern North America, parts of Africa, and the Atlantic Ocean. There was a severe heat wave in Moscow, breaking the city’s nine-decade-old temperature record more than once. However, it was cooler than average in central Russia, southern South America, and the eastern Pacific Ocean (the latter obviously because of La Niña). Continue reading

Increasing southern sea ice

This post was written for Skeptical Science as a “basic rebuttal” to the argument “Southern sea ice is increasing”.

Sea ice around Antarctica has increased over the few decades that satellites have been measuring sea ice extent. First of all, it’s worth remembering that sea ice is not to be confused with land ice. This distinction might seem obvious, but the two are often confused in media reports. Sea ice is frozen seawater floating on the surface, whereas land ice is a layer of snow that has accumulated over time on a landmass. Antarctica is losing land ice at an accelerating rate.

However, it is clear that the extent of sea ice around the coast of the continent is growing. Why? The first explanation which comes to mind is that the Southern Ocean must be cooling. But on the contrary, the Southern Ocean has warmed by around 0.5°C in the three decades since satellites began measuring sea ice trends.

The true reasons for the increasing ice are a complex set of factors. One factor is an increase in precipitation over the Southern Ocean, which means more snowfall. However, this trend is expected to reverse in coming decades as the Antarctic continues to warm.

Finally, southern sea ice is not particularly important to the climate. Unlike land ice, sea ice doesn’t affect sea levels because it’s already displacing water. And unlike the situation in the Arctic, where disappearing sea ice is making the Arctic Ocean less reflective and amplifying Arctic warming, a decline in southern sea ice would not warm the Antarctic climate. For as long as climatologists have studied it, the Southern Ocean has been almost ice-free in summer, the time of year when it would receive enough heat from the Sun to have a large effect. The issue of southern sea ice is really just a distraction which diverts our attention from the more important issue of sea ice melt in the Arctic.

In conclusion, the increase of southern sea ice does not contradict global warming. The Southern Ocean is in fact warming, the increase of sea ice is due to a variety of factors, and sea ice is not as important to the Antarctic climate as it is to the Arctic.

Americans Know Nothing About Climate Change

A new survey of 2,030 American adults (weighted according to demographics and political party allegiance) confirms what previous surveys have suggested: that the American public’s understanding of climate change is dismal. The researchers graded the participants based on percentage of questions answered correctly (although some questions were harder than others). A majority, 52%, received an F. 25% got a D, 15% a C, 7% a B, and only 1% got an A.

I am not aware of any similar surveys of Australians — I hope we are not quite as bad, but there is a powerful climate change denial lobby here too. For context, it’s not just climate science about which Americans are ignorant; it is part of a larger problem of general scientific ignorance. Surveys have consistently found that about 40% of Americans think the Earth is only a few thousand years old; about 20% do not know that a year is the time it takes the Earth to orbit the Sun.

The results are pretty depressing considering that the US is a democracy:

  • Only 63% of Americans say global warming is happening. 19% think not, and 19% are not sure.
  • Only 50% say humans are the main cause of the current warming (compared to roughly 97% of publishing climatologists). 35% say natural changes are the main cause.
  • Only 39% say that most scientists agree global warming is happening; 38% think there is a lot of disagreement among scientists. (Clearly the contrarian line of “no scientific consensus” is working.) Continue reading

Do the IPCC use alarmist language?

This post was written for Skeptical Science.

Graham Wayne has recently written rebuttals to “The IPCC consensus is phony” and “IPCC is alarmist”. But, you might say, that’s only half the story – do the IPCC present their conclusions in an alarmist way? There are many different ways you might look at this, but one of the more important ones is how the IPCC present probabilities (or “likelihoods”).

Thinking about probability does not come intuitively to the human mind. Our assessment of a risk often depends on how the probability is presented.

Suppose you are about to get on a plane and a reliable source tells you that there is a 1% chance that the plane will crash during your flight. Do you still want to get on the plane? I’m guessing you’d be having second thoughts about it.

What if the probability of a crash is 1 in 20? 1 in 10? 1 in 3? You’d probably run away screaming.

I’ll get to the point of all this shortly, but please bear with me and consider the following quote from the IPCC’s Fourth Assessment Report (AR4):

It is very unlikely that [Atlantic Ocean circulation] will undergo a large abrupt transition during the 21st century. [Source]

Are you alarmed yet? Is this an example of the IPCC using alarmist language in reporting its conclusions? Continue reading

Post-Election Wrapup

I didn’t get around to blogging on the outcome of the 2010 Australian federal election at the time because I was busy revising for an exam — but better late than never, I suppose. (You can read my pre-election wrapup here.)

The House of Representatives

The electoral results were pretty much what the pre-election polls had suggested: the Liberal-National Coalition received 43.3% of the vote, Labor 38.0%, and the Greens 11.7%. This amounts to a 5.4% swing away from Labor, a 1.3% swing to the Coalition, and a 4.0% swing to the Greens. Of the remaining 7.0% of the vote, 2.5% went to independents, 2.3% to Family First, 0.7% to the Christian Democratic Party, 0.3% to the National Party of Western Australia, and various other minor parties received less than 0.25% of the vote each. (A full list can be found here.)

Also as the polls had predicted, the national two-party-preferred (2PP) vote was very close to 50-50 (with Labor leading the Coalition at just 50.12%), but the results varied wildly from state to state. Labor received more than 55% of the 2PP vote in the states of Tasmania, Victoria, and South Australia (all in Australia’s southeast), but less than 45% in Western Australia and Queensland (west and northeast, respectively). The 2PP vote was closer in New South Wales but with the Coalition slightly ahead. Of Australia’s two main territories, Labor was only slightly ahead in the Northern Territory but way ahead in the Australian Capital Territory at 62%.

Source: Antony Green, Australian Broadcasting Corporation

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Skeptical Science posts

I haven’t been posting very often recently, and one reason is that I’ve been busy writing for another climate blog called Skeptical Science which, unlike mine, actually has a readership. Skeptical Science is run by John Cook, and basically the core of the site is an increasingly comprehensive database of rebuttals to the arguments of global warming “skeptics” (currently it includes rebuttals to no less than 122 arguments). The site has been a major inspiration for me, particularly its politically neutral fact-based approach (unlike some other climate blogs I could name).

Earlier this year I started posting comments on Skeptical Science giving detailed feedback on how to improve the site, most of which John adopted. Then a few weeks ago, John announced that the site would now include basic, intermediate, and advanced versions of each rebuttal, and asked for volunteers to help write the basic versions. So, long story short, I’ve written a number of basic rebuttals for Skeptical Science:

The empirical evidence that humans are causing global warming

Is climate science settled? Especially the important parts?

Plain english rebuttal to ‘Global warming isn’t happening’ argument

I will continue to make contributions to Skeptical Science and will link to them.