Satellites may have been underestimating the planet's warming for decades
The global warming that has already taken place may be even worse than we thought. That's the takeaway from a new study that finds satellite measurements have likely been underestimating the warming of the lower levels of the atmosphere over the last 40 years.
Basic physics equations govern the relationship between temperature and moisture in the air, but many measurements of temperature and moisture used in climate models diverge from this relationship, the new study finds.
That means either satellite measurements of the troposphere have underestimated its temperature or overestimated its moisture, study leader Ben Santer, a climate scientist at Lawrence Livermore National Laboratory (LLNL) in California, said in a statement.
"It is currently difficult to determine which interpretation is more credible," Santer said. "But our analysis reveals that several observational datasets — particularly those with the smallest values of ocean surface warming and tropospheric warming — appear to be at odds with other, independently measured complementary variables." Complementary variables are those with a physical relationship to each other.
Santer and his team compared four different ratios of climate properties: The ratio of tropical sea surface temperature to tropical water vapor, the ratio of lower troposphere temperature to tropical water vapor, the ratio of mid- to upper-troposphere temperature to tropical water vapor, and the ratio of mid- to upper-troposphere temperature to tropical sea surface temperature.
