The other day I found this great TED video where blogger David Roberts explains the significance of increasing degrees of global warming:
Archive for the ‘Global Temperature’ Category
I wrote this post for Skeptical Science.
At the recent US House of Representatives Committee on Science Space and Technology climate hearing, the Republicans called Dr. John Christy as an expert witness testifying against the global warming consensus. Unfortunately, Christy spent his time repeating a long list of climate myths, including the common contrarian refrain that “climate model output does not match up to the real world”. Let’s examine this claim.
A tale of three climate indicators
Surface temperature observations are well within the range of model projections:
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.
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 ?
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 ?
Claim: There’s no evidence that the global climate is warming. Why worry about a problem that’s invisible?
Fact: Just about any aspect of climate you care to look at does show signs of global warming.
The US National Oceanic and Atmospheric Administration have recently released their 20th annual State of the Climate report. The report is ostensibly about the climate in 2009, but because 2009 was the end of a decade the authors decided to take a longer-term view.
According to the press release, the report
draws on data for 10 key climate indicators that all point to the same finding: the scientific evidence that our world is warming is unmistakable. More than 300 scientists from 160 research groups in 48 countries contributed to the report, which confirms that the past decade was the warmest on record and that the Earth has been growing warmer over the last 50 years. Read the rest of this entry ?