Liveblogging Lomborg part 6

p 12

Claim 1: Global Warming increases cold temperatures much more than warm temperatures.
Source of Claim 1: Global observed changes in daily climate extremes of temperature and precipitation
Status of Claim:  Accurate ("the decreases in extreme minimum temperatures are greater than the increases in extreme maximum temperature").  See also graph on page 8.

Second Source:  Observed Variability and Trends in Extreme Climate Events: A Brief Review
Status of Claim: Accurate ("There has been an increase in the global mean temperature of about
0.6°C since the start of the twentieth century (Nichollset al. 1996), and that this increase is associated with a stronger warming in daily minimum temperatures than maximums"), p. 419

Third Source: Maximum and minimum temperature trends for the globe: An update through 2004
Status of Claim: Accurate ("minimum temperature increased more rapidly than maximum temperature"), though this source also says that that's been changing recently, from 1979-2004 (well, for a given value of recently).

Claim 2: Winter temperatures have been increasing most in colder regions

Source of Claim: Observed warming in cold anticyclone
Status of Claim: Accurate ("On a seasonally weighted basis, a relatively small area (12.8%) contributed
over half of the annual warming, and in the winter 26% of the area accounts for 78% of the warming.  Our analysis demonstrates that this warming is almost exclusively confined to the dry, cold, anticyclones of Siberia and northwestern North America")

  Notes: that last one goes on to say "This lack of correspondence between model results and observations causes one to question the ability of at least some GCMs to reproduce critical features of the climate in the middle- and high-latitude land regions in winter. These mischaracterizations will likely contribute to systematic errors in the forecasts of future warming".  Correct.  Computer models on their own mean nothing.


Claim 3: The United States, northern and central Europe, China, Australia and New Zealand have experienced fewer frost days.
Source of Claim:  Observed Variability and Trends in Extreme Climate Events: A Brief Review
Status of Claim: Accurate (see table on page 419)

Claim 4: Only Australia and New Zealand have seen an increase in their maximum temperatures
Source of Claim: Changes in Climate Extremes Over the Australian Region and New Zealand During the Twentieth Century
Status of Claim: False.  The paper does indeed show what Lomborg says about Australia and New Zealand - that their maximums have been going up - but it does not compare that with trends elsewhere.  Perhaps this is correct when correlated with something else, but if so, he should have spelt it out.

  Notes: Oh you are joking.  Here Lomborg has gotten confused; the important and relevant data can be found in the section he references next Observed Variability and Trends in Extreme Climate Events: A Brief Review.  See the table in question.  This also justifies his claim on no change in maximum temperatures in the US & a decrease in China.

Claim 5: In the Central England Temperature series, there has been a clear reduction in the number of cold days, but no increase in hot days.
Source of claim: The Changing Incidence of Extremes in Worldwide and Central England Temperatures to the End of the Twentieth Century
Status of Claim:  Accurate (see figure 8a, amongst others).


Overall comments: What's weird is that this is all data that supports the claims that the excitable ones get upset about - yet when they attack Lomborg they weirdly leave it all out. Cherrypicking?  Oh, perish the thought...