The current level of CO2 in the atmosphere is around 410 parts per million by volume and continues to increase with the growth of emissions due to human activities. Theoretically, if humanity continues to emit carbon dioxide into the atmosphere at present levels (about 37 billion tons per year), without reducing them, in the XXII century, the CO2 concentration can exceed 1200-1300 ppm.

Schneider, Tapio (Tapio Schneider) from the jet propulsion Laboratory of NASA and his colleagues decided to find out how the process of climate change will behave stratocumulus clouds that cover about 20% of the area of the ocean in low latitudes. These clouds are important in shaping the earth's climate by reflecting sunlight, but the resolution of contemporary global climate models do not allow to simulate the formation and dynamics on a global scale.

To work around this problem, group Schneider built a small model of the site of the atmosphere over the ocean in the subtropics by large vortices. Simulations showed that when the threshold is exceeded, the concentration of greenhouse gases in the 1300 ppm of CO2-equivalent clouds begin to break down, turning into Cumulus, and disappear, leading to a sharp rise in surface ocean temperature by eight degrees.

Again the clouds only occur after the concentration decreases significantly below this threshold to pre-industrial levels (about 300 ppm). Carbon dioxide, according to scientists, will hinder the transfer of heat from the upper layers of clouds that reduce the temperature difference between the upper and lower layers and, as a consequence, the speed of "mixing" of clouds. Standard global climate models do not show this effect at concentrations up to nine thousand parts per million.

The study authors note that their assumptions can also help explain the mystery of the paleoclimate of the Eocene about 50 million years ago the Arctic was ice-free: existing climate models indicate that for such temperatures, the required CO2 concentration of more than four thousand parts per million, or about two times higher than the estimated concentration in the period of paleoclimatic data.

If the hypothesis of scientists about the disappearance of clouds is correct, this could explain the sharp warming and the concentration of carbon dioxide.

Source: https://42.tut.by/627896

Tags: climate