It's time we faced up to the fact that there is an alternative reality, an alternative media with no respect for truth whatsoever. It started out as an effort to inject lies into the mainstream media, but now survives on its own and provides pseudo-information to a significant swath of the country.
The HadCRUT is a combination of land air temperature anomalies (Jones, 1994, CRUTEM1) and sea surface temperature anomalies (Parker et al., 1995) on a 5° x 5° grid-box basis. It' issued by the UK's Hadley Climate Research Unit ("HadCRU"). (I haven't spent much time with the observations community but I'd guess it's pronounced Had-Crew-Tee. Anyone?)
OK, so, everything consistent with the other branches of climate science, right? The biggest open question is why there is extra lower tropospheric warming in some observational data. It would be modestly dynamically important if these data sets prove correct because it would call into question some modeling details, but presently (as of '06) the balance of evidence is against them. (More recent news on this front would be appreciated.)
- For observations since the late 1950s, the start of the study period for this Report, the most recent versions of all available data sets show that both the surface and troposphere have warmed, while the stratosphere has cooled. These changes are in accord with our understanding of the effects of radiative
forcing agents and with the results from model simulations.
- Since the late 1950s, all radiosonde data sets show that the low and mid troposphere have warmed at a rate slightly faster than the rate of warming at the surface. These changes are in accord with our understanding of the effects of radiative forcing agents on the climate system and with the results from model simulations.
- For observations during the satellite era (1979 onwards), the most recent versions of all available data sets show that both the low and mid troposphere have warmed. The majority of these data sets show warming at the surface that is greater than in the troposphere. Some of these data sets, however, show the opposite - tropospheric warming that is greater than that at the surface. Thus, due to the considerable disagreements between tropospheric
data sets, it is not clear whether the troposphere has warmed more than or less than the surface.
- The most recent climate model simulations give a range of results for changes in global-average temperature. Some models show more warming in the troposphere than at the surface, while a slightly smaller number of simulations show the opposite behavior. There is no fundamental inconsistency among these model results and observations at the global scale.
- Studies to detect climate change and attribute its causes using patterns of observed temperature change in space and time show clear evidence of human influences on the climate system (due to changes in greenhouse gases, aerosols, and stratospheric ozone).
- The observed patterns of change over the past 50 years cannot be explained by natural processes alone, nor by the effects of short-lived atmospheric constituents (such as aerosols and tropospheric ozone) alone.
Since its temperature graphs you want to talk about, note that your GISS graphs have come under heavy attack for their use of data affected by station dropout and poor siting. More valid graphs of atmospheric temperature trends come from the UAH satellite data - and they show essentially no change over the 30 years of data collection.
Note the caption: Difference between NOAA and UAH and RSS. (Larger image link) This agrees with the preceding paragraph: "the difference started small but is now approaching 0.5 C". Now if it were true, that would be a big deal.
There is a problem in that d'Aleo does not point out that the proposed discrepancy is over land only.
Update: The preprint is published on the web (PDF), so it seems blogworthy. Any opinions here on how much sense it makes, or links to same elsewhere, appreciated.