Hotter nights flooding the atmosphere with more carbon: Study

Washington: Hotter nights may actually wield much greater influence over the planet's atmosphere as global temperatures rise and can eventually lead to more carbon flooding the atmosphere, researchers from Princeton University have warned.

Since measurements began in 1959, night-time temperatures in the tropics have had a strong influence over year-to-year shifts in the land's carbon-storage capacity or “sink”.

Earth's ecosystems absorb about a quarter of carbon from the atmosphere, and tropical forests account for about one-third of land-based plant productivity.

During the past 50 years, the land-based carbon sink's "interannual variability" has grown by 50 to 100 percent, the researchers found.

The researchers used climate and satellite-imaging data to determine which of various climate factors -- including rainfall, drought and daytime temperatures -- had the most effect on the carbon sink's swings.

They found the strongest association with variations in tropical night-time temperatures which have risen by about 0.6 degrees Celsius since 1959. Just as warm nights make people more active, it does for the plants too. Although plants take up carbon dioxide from the atmosphere, they also internally consume sugars to stay alive.

The researchers found that yearly variations in the carbon sink strongly correlated with variations in plant respiration. Night-time temperatures have been increasing faster than daytime temperatures and will continue to rise faster.