Large changes in climate likely over next century

A new research has led to the confirmation of the mainstream scientific view that large changes in the climate are likely over the next century.

The research collected daily global measurements of carbon dioxide and water vapour in a key part of Earth's atmosphere with the help of the Atmospheric Infrared Sounder (AIRS) instrument on NASA's Aqua spacecraft.

The new data have been extensively validated against both aircraft and ground-based observations.

They give users daily and monthly measurements of the concentration and distribution of carbon dioxide in the mid-troposphere - the region of the atmosphere located between 5 and 12 km, or 3 to 7 miles, above Earth's surface and track its global transport.

Users can also access historical AIRS carbon dioxide data spanning the mission's entire seven-plus years in orbit.

The product represents the first-ever release of global daily carbon dioxide data that are based solely on observations.

In a major finding, scientists using AIRS data have removed most of the uncertainty about the role of water vapour in atmospheric models.

The data are the strongest observational evidence to date for how water vapour responds to a warming climate.

"The argument that the scientific community does not understand water vapour is one of the most durable urban legends in the climate change debate," said Andrew Dessler, a climate scientist at Texas A and M University.

"AIRS temperature and water vapour observations have corroborated climate model predictions that the warming of our climate produced by carbon dioxide will be greatly exacerbated - in fact, more than doubled - by water vapour," he added.

AIRS measurements of water vapour reveal that water greatly amplifies warming caused by increased levels of carbon dioxide.

Comparisons of AIRS data with models and re-analyses are in excellent agreement.

"The implication of these studies is that, should greenhouse gas emissions continue on their current course of increase, we are virtually certain to see Earth's climate warm by several degrees Celsius in the next century, unless some strong negative feedback mechanism emerges elsewhere in Earth's climate system," Dessler said.