James Lovelock’s climate change U-turn

Lovelock’s recent statements on climate change don’t seem to take account of the latest data. Jonathan Cobb

Recent statements by James Lovelock, the distinguished physicist, are not easy to reconcile with his statements, writings and books over the years, including The Vanishing Face of Gaia; The Revenge of Gaia and others.

As recently as March 30th, 2011, it was reported: “Professor James Lovelock, the scientist who developed Gaia theory, has said it is too late to try and save the planet. The man who achieved global fame for his theory that the whole earth is a single organism now believes that we can only hope that the earth will take care of itself in the face of completely unpredictable climate change.”

But now Lovelock says:

The world has not warmed up very much since the millennium. Twelve years is a reasonable time … it (the temperature) has stayed almost constant, whereas it should have been rising - carbon dioxide is rising, no question about that …

The problem is we don’t know what the climate is doing. We thought we knew 20 years ago. That led to some alarmist books – mine included – because it looked clear-cut, but it hasn’t happened …

The climate is doing its usual tricks. There’s nothing much really happening yet. We were supposed to be halfway toward a frying world now.

Figure 1. Global land temperature estimates T(avg), smoothed by a 12-month moving average. The temperature anomaly is the difference between the estimated temperature and the mean in the period 1950-1980 for each temperature series. Note the similarity of many of the short-term fluctuations with periods 2-15 years. The Berkeley Earth data were randomly chosen from 30,964 sites that were not used by the other groups. http://berkeleyearth.org/available-resources/

Unfortunately, these statements by James Lovelock are inconsistent with up-to-date climate data sets. These indicate:

  1. the 1st decade of the 21st century includes unprecedented instrumentally measured peak temperature records, including a peak temperatures about ~2005-8 of up to 1.1 degrees Celsius above the 1950-1980 reference mean measured by NOAA, NASA and HadCRU, as compiled by the Berkeley Earth Surface Tempeature analysis group (see Figure 1). According to NOAA, mean temperature maxima between 1998 and 2010 have risen by ~0.17 degrees Celsius (0.014C/year), whereas mean temperature minima rose between 2000 and 2009 by ~0.2 degrees Celsius (0.022C/year) (see Figure 1)
    Figure 2: Anthropogenic sulphur dioxide emissions 1850-2005 Atmos.Chem.Phys
  2. the mean temperature rise gradient between ~2000-2010 was somewhat shallower than the mean maxima during 1975-1998 (0.43C/year) which is accounted for by:
    • a sharp reduction in the emission of SO₂ from about 1974-5 to about ~2000, which decreased the direct and indirect aerosol shielding effect and cloud aerosol albedo shielding effect (see Figure 2). A renewed rise in SO₂ emissions from about 2000, largely from China, accounts for part of the relative cooling at that stage
    • the minima in the 11-years sun-spot cycle from about 2002 (see Figure 3)
    • the prevalence of La Niña conditions toward the end of the first decade of the 21st century (see Figures 4 and 5).
Figure 3: Sun spot numbers between 1950 and 2011. http://solarscience.msfc.nasa.gov/images/Zurich_Color_Small.jpg

It is a strawman argument to expect temperature trends to change smoothly, or to highlight periods when temperatures have risen at low rates or even declined, and at the same time overlook the mean decadal trend where measured temperatures have risen during the 20th – early 21st centuries by more than 1.0 degrees Celsius (see Figure 1).

A far greater rise is currently masked by sulphur aerosols of short (one to two years) atmospheric residence time, without which mean global temperatures would have risen above 2.0 degrees C since the early 20th century.

Figure 4: ENSO cycles between 1880-2011. “ zoomable="true” /> Given the above it remains a mystery as to the nature of the evidence or reasons underlying James Lovelock’s statements. It is particularly perplexing, since 20th century greenhouse and temperature rise rates are orders of magnitude higher than during any previous period, excepting intra-glacial Dansgaard-Oeschger cycles (see Table 1) Popular notion on media and <a href= http://www.bom.gov.au/climate/current/soihtm1.shtml

“Everyone is entitled to his opinions but not to his facts” (Senator Daniel Moynihan)

Figure 5: 1950-2011 global temperature anomalies, El-Nino phases and La-Nina phases “ zoomable="true” /> <image id= http://www.ncdc.noaa.gov/sotc/global/2011/13