Skeptics over global warming have jumped on news that Mars is heating up to back their skepticism that humans are causing global warming on Earth.
The research, coming from U.S. planetary scientists, suggests that Mars warmed by about 0.65C from the 1970s to the 1990s. This is similar to Earth’s 0.6C average temperature rise during the 20th century.
“It could be coincidental or it might be the needle in the haystack,” said climatologist William Kininmonth, former head of the National Climate Centre in Melbourne, Australia.
Kininmonth said that the research, which was published in the journal Nature, showed that there was enough natural climate variability to explain global warming on Earth.
Not all scientists agree with that, however, climate scientist Neville Nicholls at Monash University in Melbourne.
“The paper is interesting but it hasn’t got anything to do with the question of human impact on global warming on Earth,” Dr Nicholls said. “It’s not an excuse to argue that humans are not causing global warming on Earth.”
The research was conducted by a team led by Lori Fenton at the NASA Ames Research Center in Moffett Field, Calif.
The team used a computer model based on those devised to study global warming on earth. They then added features of the Red Planet such as a cold, airless surface and a shifting south polar ice cap, and subtracted Earth’s oceans and atmosphere.
Fenton’s group discovered that annual variation in the solar radiation reflected from the Martian surface, known as albedo, contributed to the warming by causing more blowing dust.
The results show the importance of albedo to the Marian climate. It also provides a better documentation that albedo changes actually occur, according to Mars atmospheric modeler Tim Michaels of the Southwest Research Institute in Boulder, Colo.
“I certainly think that it has generally warmed the atmosphere,” he says, assuming the albedo changed gradually.
Unlike Earth’s global warming, the Martian version would depend entirely on dust patters, which can shift.
“If we have a big dust storm tomorrow, this could all change like that,” Michaels said.
The Nature paper precedes the second report from the fourth IPCC review, which is to be released tomorrow.