Watts temperature under fire -including by co-author

I blogged last week on a report by Antony Watts which found the increase in US surface temperature in the last 20 years was less than previously reported. It was all about appropriate adjustments to station data.

The Washington Post blogger Jason Samwnow blogs:

The blogosphere has quickly pointed out two problems with Watts’ estimates:

1) Independent satellite data – which Watts posts on his blog each month and has stood behind – indicate a warming over the U.S. closer to NOAA’s estimate. This point was raised by ClimateAudit blogger Steven McIntyre: “Over the continental US, the UAH satellite record shows a trend of 0.29 deg C/decade (TLT) from 1979-2008,” McIntyre said.

Interestingly, McIntyre is listed as a co-author of the Watts paper but begins a blog post expressing “puzzlement at Anthony’s [Watts’press release] announcement”and qualifies his involvement as “very last minute and limited”. And he admits to not having “parsed” parts of the Watts study.

2) Watts’ failure to make certain adjustments to the raw data, as NOAA has done, is a serious flaw knowledgeable bloggers say. Specifically, Watts did not apply a time of observation bias correction according to Howard Universitychemistry professor Josh Halpern, who blogs under the pseudonym Eli Rabett. McIntyre also addressed this problem: “There is a confounding interaction with TOBS [time of observation] that needs to be allowed for, as has been quickly and correctly pointed out.”

Also the listed co-author has blogged:

People have quite reasonably asked about my connection with the surface stations article, given my puzzlement at Anthony’s announcement last week. Anthony described my last-minute involvement here.

As readers are probably aware, I haven’t taken much issue with temperature data other than pressing the field to be more transparent. The satellite data seems quite convincing to me over the past 30 years and bounds the potential impact of contamination of surface stations, a point made in a CA post on Berkeley last fall here. Prior to the satellite period, station histories are “proxies” of varying quality. Over the continental US, the UAH satellite record shows a trend of 0.29 deg C/decade (TLT) from 1979-2008, significantly higher than their GLB land trend of 0.173 deg C/decade. Over land, amplification is negligible.

The satellite data is generally seen as accurate, and supports the records that show around 0.3 degree warming a decade. It is worth noting that even if you think Watts is right that it is lower at 0.15 – what is not disputed that temperatures are increasing. It is also very basic uncontested science that greenhouse gases in the atmosphere will have a warming effect. What is contested is how large and fast that warming will be.