Posted by
Aaron McLucas on Sunday, June 08, 2008 11:32:31 AM
It would seem we have an error in the data:
A longstanding puzzle in Earth’s climate record has just been solved. Between 1940 and 1970 — right in the middle of a steady, post-Industrial warming trend — global mean temperatures mysteriously dropped, with the most precipitous drop in 1945. Experts have debated a handful of explanations, including an increase in anthropogenic sulfate emissions that blocked sunlight and anomalous atmosphere-ocean interactions. But a new study suggests that the story is much simpler: An abrupt change in how scientists measured temperatures above the ocean, not the climate itself, explains the slump.
Lead author of the study, David Thompson of Colorado State University in Colorado Springs found out how those measurements were being done.
From 1942 to August 1945, 80 percent of observations came from U.S. ships, which took their readings of sea-surface temperatures as seawater entered the engine cooling system. At the war’s end, ships from the United Kingdom resumed data collection as well. Within a year, half the observations in the record were British, with only 30 percent from U.S. ships. British sailors collected sea-surface temperature readings by dropping uninsulated buckets from the deck, reeling them up full of water, and measuring the temperature. While the engine room method tends to inflate measurements a bit because the water is near the hot ship engine, the bucket method tends to deflate them as the water cools when contacting ambient air, the team wrote. So that baffling mid-century downturn, they say, is an artifact of instrumentation.
If this is how we measure sea temperature, than I think the whole record is up for debate. But they address that too.
Although the changes "could be another source of skepticism for those inclined to be skeptical” about climate models, Forest says, it won’t change most scientists’ verdict on the last hundred years: The world is warming. More scrupulous study only underscores their confidence. Forest, for one, is excited. “We’re going to continue to see updates in the next decades as we come up with more clever ways to analyze the data,” he says. “That’s the way the science moves forward.”
Since the temperatures are going to be corrected upwards, it will be more in line with the upward trend which bodes well for the believers rather than the skeptics. As for the ways in which data is collected, I would think they could come up with a more 'clever' idea.