Current state-of-the-art global climate models predict substantial warming in response to increases in greenhouse gases such as carbon dioxide. The models, though, disagree widely in the magnitude of the warming we can expect. The disagreement among models is mainly due to the different representation of clouds. Some models predict that global mean cloud cover will increase in a warmer climate and the increased reflection of solar radiation will limit the predicted global warming. Other models predict reduced cloudiness and magnified warming.(more…)
The troposphere, the lower part of the atmosphere closest to the Earth, is warming in ways that are broadly consistent with both theoretical expectations and climate models, according to a new scientific study from the National Oceanic and Atmospheric Administration (NOAA) and the NOAA-North Carolina State University Cooperative Institute for Climate and Satellites (CICS).
Since the development of the first climate models in the 1960s, the troposphere has been projected to warm along with the earth’s surface because of the increasing amounts of greenhouse gases in the atmosphere. This expectation has not significantly changed even with major advances in climate models. (more…)
Scientists have long known that large volcanic explosions can affect the weather by spewing particles that block solar energy and cool the air.
Some suspect that extended “volcanic winters” from gigantic eruptions helped kill off dinosaurs and Neanderthals.
In the summer following Indonesia’s 1815 Tambora eruption, frost wrecked crops as far away as New England, and the 1991 blowout of the Philippines’ Mount Pinatubo lowered average global temperatures by 0.7 degrees F — enough to mask the effects of greenhouse gases for a year or so. (more…)
WASHINGTON — Scientists have long known that heat-absorbing components of Earth’s atmosphere, such as clouds and certain gases, prevent our planet from being an ice-covered ball. Now a study, for the first time, comprehensively calculates the relative contributions of the components responsible for that heating, known as the greenhouse effect.
Besides clarifying an important aspect of climate science, the study also demonstrates that rising concentrations of one heat-trapping gas — carbon dioxide — leads to much more greenhouse warming than just the heat the gas absorbs directly itself.
Various studies have looked at the contributions of water vapor, CO2, and other greenhouse gases. But none had systematically estimated the contributions of each of the main players, says climate scientist Gavin Schmidt of NASA Goddard Institute for Space Studies, and lead author of the new research. (more…)
