[Illustrations, footnotes and references available in PDF version]
“Global cooling is really ‘global warming’”
The scare: On 2 January 2009, the Wall Street Journal wrote one of a series of articles apparently co-ordinated throughout the generally alarmist news media throughout the holiday season, trying to overcome the problem posed for “global warming” alarmists by the fact that global mean surface temperatures have been on a downtrend for eight straight years (Figure 1):
Eight straight years’ global temperature downtrend: The authoritative SPPI composite index of global mean surface temperature anomalies, taking the mean of two surface and two satellite datasets and updated through November 2008, shows a pronounced downtrend for eight full years. Not one of the climate models relied upon by the IPCC had predicted this downturn. The pink region shows the IPCC’s projected rates of temperature increase: the thick red straight line – entirely outside and below the pink region shows the real trend, calculated as the least-squares linear regression on the composite temperature anomalies.
In the article, entitled The Warming Earth Blows Hot, Cold and Chaotic, the Wall Street Journal starts out by admitting that “three independent research groups” had concluded that 2008 was a comparatively cool year. Even so, the article said, the year’s global temperature was the 9th or 10th warmest since reliable record-keeping began in 1850, though it was the coldest since the turn of the 21st century.
The article, having mentioned last year’s cooling through gritted teeth, but somehow not having mentioned that there has been a downtrend in temperatures not for one year but for eight straight years, then lists a series of bugaboos nearly all of which depend on the weather having warmed over the past decade when in fact it has cooled.
The article frets that “higher temperatures make weather patterns more unstable”; that “the planet has grown steadily warmer in recent decades”; that “almost all of the warming in North America has taken place since 1970”; that “the effects of rising temperatures are accelerating”; that “ice loss is happening faster than the models are showing”; that “Greenland has lost an area of ice ten times the size of Manhattan”; that “Alaska’s low-lying ice-fields are disappearing”; that “tropical storms can be expected to increase by 6% every 10 years”; that 2007’s Atlantic hurricane season was “the fourth most active in 64 years”; that “solar heat is the energy that drives the world’s weather, and greenhouse gases such as carbon dioxide and methane are allowing more of that energy to build up in the atmosphere every year”; and that “so many subtle changes in so many different places, building up decade after decade, add up to something more than the weather’s natural variation”.
The truth: Since global temperatures have followed a cooling trend for eight straight years (or 11, if one goes back to the exceptionally warm el Nino year of 1998), most of the supposed recent consequences of “global warming” mentioned in the article – to the extent that the phenomena mentioned have occurred at all – cannot possibly have arisen because of “global warming”, because there has not been any. What is more, it is not only the atmosphere but also the oceans that have shown a cooling trend. Not one of the models relied upon by the IPCC had forecast the cooling. The pink region in Figure 1 is the IPCC’s range of projections for future “global warming”, starting in 2001. It bears no correlation whatsoever to the observed downtrend. From January 2009, SPPI will be publishing a monthly-updated CO2 Report that will make these and other data regularly available, and will help to dispel climate myths such as those perpetrated and perpetuated in the Wall Street Journal.
“Higher temperatures make weather patterns more unstable”: In fact, the reverse is true. The world has warmed by 0.7 degrees C since 1900: yet, despite this warming, the number of landfalling Atlantic hurricanes shows no trend at all throughout the 20th century; the number of intense tropical cyclones and typhoons has been falling throughout the 30-year period of the satellite record; and it is settled science that, outside the tropics, warmer weather will generally mean fewer storms, because the differential between warmer and cooler parts of the globe will diminish.
“The planet has grown steadily warmer in recent decades”: In fact, the reverse is true. The fastest rate of growth in global temperature, at a rate equivalent to almost 2 degrees Celsius per century, was between 1910 and 1930. No “recent decade” has matched that warming rate, though 1975-1998 came close. Between 1940 and 1975, and again between 2001 and the present, global temperatures have exhibited a downtrend. In fact, the current warming began 300 years ago, at the end of the Maunder Minimum, a 70-year period when there were very few sunspots on the face of the Sun. Between 1700 and 1735, according to the world’s oldest instrumental temperature dataset, the temperature in central England rose by 2.2 degrees C, equivalent to 6.3 C/century, or about nine times the warming rate seen in the 20th century. The warming of the planet parallels the increase in the Sun’s activity between the end of the Maunder Minimum 300 years ago and the end of the 70-year solar Grand Maximum in 1998. During the Grand Maximum, the Sun was more active, and for longer, than during almost any similar previous period in the past 11,400 years (Solanki et al., 2005). For at least 275 of the 300 years’ warming, humankind cannot have had anything much to do with the warming. Given the inexorable increase in solar activity throughout the past 300 years (see Hathaway, 2004: Figure 2), it is no surprise that the weather is warmer now than it was 30 or 50 or 100 or 200 or 300 years ago.
Solar activity, as measured by sunspot numbers, increased sharply between the end of the sunspotless Maunder Minimum in 1700 and the peak of the 70-year Solar Grand Maximum in the early 1960s. During the Grand Maximum, solar activity was greater, and for longer, than during almost any similar previous period in the 11,400 years since the end of the last Ice Age. Source: Hathaway et al., 2004.
Since there has been a prolonged period of warming, nearly all of it natural, the warmest years were also clustered among the most recent years. None of this is surprising, none of it is alarming, and none of it points to anything other than a minuscule and harmless anthropogenic contribution to warming.
“Almost all of the warming in North America has taken place since 1970”: In fact, it has done no such thing. The warmest year on the North American continent was 1934. However, at least one of the major global datasets has been manipulating the raw data so as to reduce the previously-recorded warming during the 1920s and 1930s, while artificially increasing the actually-observed warming rate in the present, thereby making it appear that most of the warming in North America is recent. Details of this disturbing tampering, with examples both from individual temperature stations and also from a global temperature dataset, will be revealed in future issues of the SPPI’s authoritative Monthly CO2 Report.
“Ice loss is happening faster than the models are showing”: In fact, there has been no trend in global sea-ice extent throughout the 30-year satellite record, as Figure 3 demonstrates –
No trend for 30 years in global sea-ice extent. Source: University of Illinois.
The generally-alarmist news media have concentrated chiefly on sea ice in the Arctic, because in the summer of 2007 more than a quarter of the usual summer sea-ice suddenly melted. However, NASA published a paper recently that made it clear that the chief reason for this sudden (and temporary) melting was a combination of warm currents and winds carrying tropical heat poleward. This had little to do with “global warming”, and has substantially reversed itself since. Indeed, the rate of sea-ice formation in October 2008 was the most rapid ever observed. Current Arctic sea-ice extent is barely distinguishable from the extent observed by the satellites on the same day in 1980, the first year in which satellite coverage allowed the extent of the ice to be reliably monitored (Figure 4) –
Arctic sea-ice extent (purple) on 3 January 1980 and 2 January 2009: there has been very little loss of Arctic sea ice since 1980, and this loss has been more than made up by gains in Antarctic sea-ice. Source: University of Illinois.
“Since 2003, Greenland has lost an area of ice ten times the size of Manhattan”: In fact, this quantity is trivial and (perhaps deliberately) misleading. Manhattan Island is 22.7 square miles, so Greenland’s ice loss since 2003 is said to be 227 square miles. In 2000, according to the CIA world fact book, the Greenland ice-sheet was 677,855 square miles in extent. So the ice loss since 2003 represents one part in 3000 of the ice sheet, or 0.03%. Such trivial changes in ice cover are well within long-run natural variability: indeed, 850,000 years ago the entire Greenland ice sheet melted away, and anthropogenic “global warming” cannot have been to blame, for we were not there. Furthermore, one should contrast the negligible change in area with the change in mass that has occurred recently. For instance, Johannesen et al. (2005) report that the mean thickness of the entire Greenland ice sheet grew by 2 inches per year for 11 years from 1993 to 2003, gaining almost 2 feet in thickness.
“Alaska’s low-lying ice-fields are disappearing”: In fact, Alaska had a record-cold winter in 2007/8, then a record-cold summer in 2008, and is now experiencing its second very cold winter in a row. The fact that low-lying ice-fields have been disappearing is not in the least surprising after 300 years of warming, 275 of which were unquestionably natural.
“Tropical storms can be expected to increase by 6% every 10 years”: In fact, the reverse is true. As already noted, the number of intense tropical hurricanes has remained static for a century, and the number of intense tropical cyclones and typhoons has been falling throughout the 30-year period of the satellite record. There is no scientific basis whatsoever for the Wall Street Journal’s assertion, as a cursory look at the cyclone-frequency and cyclone-intensity records would have revealed. The Accumulated Cyclone Energy Index, a two-year running sum of the intensities of all tropical storms, has been maintained for 30 years. Its lowest value on record was for October 2008, notwithstanding the relatively active Atlantic hurricane season in 2007.
“Greenhouse gases such as carbon dioxide and methane are retaining more of the Sun’s energy”: So they are, but not very much more. The atmospheric concentration of methane (present only in parts per billion) did not rise between 2000 and 2007, and the atmospheric concentration of carbon dioxide has been rising linearly since 2000 at a rate of only 200 parts per million per century. At that rate, the warming from carbon dioxide will not be more than 1.8 C: i.e. only half of the 3.6 C predicted by the IPCC in 2100. And that is before removing the numerous exaggerations in the IPCC’s method of calculating the effect of a given increase in CO2 concentration on temperature, which would bring the anthropogenic warming down to well below 0.5 C/century. It is generally accepted that any warming of less than 2 C over the coming century will be largely harmless and beneficial.
“Subtle changes, adding up decade after decade, amount to more than the climate’s natural variation”: In fact, they don’t. For a start, as previously noted, many of the changes are so small that they are well within the very large variations that have taken place in the climate of the past. In any event, the end of the present decade will prove to have been substantially cooler than the beginning, notwithstanding the steady increase in CO2 concentration throughout. In the past, one might have relied upon the Wall Street Journal to check its facts, and to present both sides of the story – especially the factually-true side. But, on “global warming”, no news medium can now be trusted to check even the elementary and readily-available facts recorded here. End of scare.