Study Supports Global Warming, And Need For Good Data

Continued from page 1

To improve the quality of the data, the team had to consider the fact that measuring technologies have changed over the last fifty years, and local climates may have altered independently. Some of the stations may have moved too.

Above all, the effect of localised warming on the data, by cities, had to be factored out. About 0.2 percent of the world is urban, and temperatures there have definitely gone up, by 2ºC or more. But that has a small effect on the temperature of the whole planet, and needs to be excluded.

Overall, two thirds of the world’s weather stations recorded warmer temperatures, by up to 1-2ºC, and one third showed cooler temperatures. So Muller concludes the world is warming. “Global warming is real,” he says in the WSJ. “Perhaps our results will help cool this portion of the climate debate. How much of the warming is due to humans and what will be the likely effects? We made no independent assessment of that.”

Next, the group is going to look at the things it didn’t cover – in particular, temperature rises over the oceans, which are completely outside the data it has. Beyond that, it’s possible to use tree rings to extend the data back even further.

More open data

This isn’t the end of the wars over climate change – or at least the overheated reporting of supposed wars in the media. The Daily Mail has taken an interview with Judith Curry, one of the BEST authors, and inflated it into an argument with Muller, over an interpretation of the figures which suggests that warming may have slowed or stopped in the last decade.

In fact, Curry’s blog reveals that her disagreement, if any, with BEST is very slight, and mostly emerges from the media treatment of the results. Her comments, which the Mail hyped, were a response to the headline of Muller’s article, which in turn had been inflated by the Wall Street Journal.  Muller actually wanted to say the data would “cool the warming debate”, not spell the “end of skepticism”.

This week, both are presenting data at the third Santa Fe Conference on Global and Regional Climate Change.

What is good about all this is that, while scientists get on with their professional lives, the data is in the public domain. The Berkeley Earth team results have been sent to four peer-reviewed journals, but the full data set and a summary of its results, is already available on the group’s own site.  That’s 1.6 billion temperature measurements, from fifteen different archives, across 60 years – about 253Mbyte in all.

How open should it be though? There’s an interesting discussion on the Berkeley Earth site about the practicalities of peer-review, and the fact that results also need to be discussed at an earlier stage in “preprint” form, which can raise a danger of misreporting. Berkeley decided to go for openness, while the peer review process is going on.

In my view that shows we have all learned from the Climategate experience.