Posts Tagged ‘Temperature Records’


2010: A Year of Record Warmth and Weird Weather

24 January 2011

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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The Fake Scandal of Climategate

23 November 2010

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. Read the rest of this entry ?


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

23 October 2010

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). Read the rest of this entry ?


Skeptical Science posts

25 September 2010

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.


Mid-Year Update on Global Temperatures

18 July 2010

NOAA’s National Climatic Data Center (NCDC) have announced that the Earth has just experienced its warmest June on record, 0.68°C warmer than the 20th-century June average of 15.5°C. Most of the globe was warmer than usual, with the highest temperature anomalies seen in eastern and western Asia, eastern North America, western South America, and most of the Atlantic Ocean. The only surface temperatures much cooler than average were in the eastern Pacific and Southern Oceans. The warmest June is particularly notable in that it follows the warmest March, April, and May.

(Global temperatures are usually given as anomalies relative to a 20th century average because they are easier and more useful to compare than absolute temperatures. The last month with a temperature below average was February 1985.)

Let’s quickly recap the year so far. It began with an unusually cold winter in northern land areas, related to the Arctic Oscillation (AO), which in February 2010 was at its most negative value on record, moving heat to Arctic regions. Despite the unfortunate and disproportionate impact this had on public opinion, January was a relatively warm month globally, and the Southern Hemisphere had its warmest February on record. Read the rest of this entry ?


Global Warming Contrarians Part 1.1: Amateur Temperature Records

9 July 2010

After a two-month hiatus, I’ve finally completed the next installment in my increasingly non-linear series of posts examining the (mostly bad) arguments against the reality of global warming. Originally I had planned out a sort of arc of subjects to cover, but as I learn more about climate science, I find I want to go back to what I’ve written previously and add new information, or explain things in a different way — that’s why I’m calling this post Part 1.1. So here’s a continued version of my argument in favor of the surface temperature record. I discuss one of the latest trends in the climate blogosphere: amateur temperature records.

Claim: The surface temperature record cannot be trusted.

Fact: Recent developments should make us even more confident that the record can indeed be trusted.

As I’ve mentioned before, there are three main surface temperature records, compiled by NOAA’s National Climatic Data Center (NCDC), NASA’s Goddard Institute for Space Studies (GISS), and the University of East Anglia’s Climatic Research Unit (CRU), respectively. There is also at least one other that is lesser known: that of the Japan Meteorological Agency (JMA). All of these analyses have been compiled by professional research organizations and published in peer-reviewed scientific journals. All of them converge on a common result: the Earth’s surface has warmed about 0.7°C in the last 100 years, and about 0.18°C/decade in the last 25 years. So all the records taken together can be seen as a sort of “consensus temperature record”, in which the observed warming is well outside the error bars.

Unfortunately, some members of the public are inclined to believe that this convergence is all part of a huge conspiracy, that scientists are not allowed to get results that contradict the pre-determined conclusions of the so-called “establishment”. This view is entirely at odds with my understanding of how science works, but it’s a depressingly common one. It’s also a difficult view to argue with, because the more positive results you cite, the bigger the conspiracy must be in the eyes of the conspiracy theorists. But what if there was a global temperature analysis entirely independent of the scientific establishment? Read the rest of this entry ?


Global Warming Contrarians Part 2.1: Cooling Trend or Noise?

12 May 2010

In Part 2 of this series of posts examining the (mostly bad) arguments against the reality of global warming, I debunked the oft-heard claim that global warming stopped in 1998. Basically, the people who make that claim are just joining endpoints, rather than looking at the trend from 1998 to now. But there is a slightly more sophisticated version of that argument, which does actually look at the trend. It goes something like:

Claim: There’s been global cooling since 2001 (or 2002), and no significant warming since 1995.

Fact: Firstly, the exact trend varies from one record to another. The NCDC record shows a slight negative trend for 2001-2009, and a more negative trend for 2002-2009. GISTEMP shows a very slight positive trend for 2001-2009, and a negative trend for 2002-2009. Both trends are decidedly negative in the HadCRUT3 record. But all three records show a positive trend for 2000-2009.

In earlier posts I’ve mainly cited the NCDC record when talking about surface temperatures; for the sake of consistency, I’ll continue to do so here. According to NCDC, the trends are +0.07°C/decade for 2000-2009, -0.03°C/decade for 2001-2009, and –0.08°C/decade for 2002-2009. So technically, we have seen about nine years of “cooling”. But is that enough to indicate a change in the long-term trend? Read the rest of this entry ?