greenhouse effect

Record Carbon Dioxide Levels | Earth Wise

June 29, 2021 By EarthWise Leave a Comment

The coronavirus pandemic caused a temporary dip in the burning of fossil fuels around the world as many human activities were diminished or curtailed entirely. Despite this, the amount of carbon dioxide in the atmosphere set a record in May, reaching the highest levels in human history.

Scientific instruments atop the Mauna Loa volcano in Hawaii measured an average of 419 parts per million for the month, according to analysis from both the Scripps Institution of Oceanography and the National Oceanic and Atmospheric Administration.

This level is about half a percent more than the previous record of 417 ppm, set in May of 2020. Carbon dioxide is the largest greenhouse gas contributor driving global warming and, according to scientists, there hasn’t been this much of it in the atmosphere for millions of years.

Global emissions of carbon dioxide were actually 5.8 percent lower in 2020 than 2019, as a result of pandemic lockdowns. This was the largest one-year drop ever recorded. But humanity was still responsible for emitting more than 31 billion tons of carbon dioxide last year. About half of that CO2 is absorbed by the world’s trees and oceans, but the other half lingers in the atmosphere for thousands of years, gradually warming the planet via the greenhouse effect.

As long as we keep emitting carbon dioxide, it is going to continue to pile up in the atmosphere. The only way to stop it is for the world’s nations to zero out their net emissions, mostly by switching away from fossil fuels to technologies that do not emit carbon dioxide, such as electric vehicles fueled by wind, solar, or nuclear power.

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Carbon Dioxide in Atmosphere Hits Record High Despite Pandemic Dip

Photo, posted August 7, 2013, courtesy of Gerry Machen via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Clouds And Global Warming | Earth Wise

March 9, 2020 By EarthWise Leave a Comment

Recent climate models from multiple organizations project that the amount of warming that doubling atmospheric carbon dioxide would cause would be much more than previously estimated. And one of the significant changes to the models relates to the role of clouds.

Clouds have long been a major uncertainty in climate calculations. Clouds can shade the earth and thereby provide cooling. But clouds can also trap heat. Which effect dominates depends on how reflective the clouds are, how high up they are, and whether it is day or night. The dynamics of clouds are complicated.

If you fly across the ocean, you will see blankets of low clouds extending for hundreds of miles. These marine stratus and stratocumulus clouds predominantly cool the Earth. In fact, they shade roughly a fifth of the oceans and reflect 30-60% of the solar radiation that hits them back into space.

Recent studies indicate that as global temperatures rise, these clouds are likely to become thinner or burn off entirely, leaving more clear skies through which the sun may add another degree Celsius or more to global warming.

The concerns about clouds are part of the larger issue about feedbacks in warming the world. It has long been clear that the greenhouse effect of doubling CO2 levels in the atmosphere would raise global temperature. But there are amplifying feedback effects. Melting large areas of snow and ice reduces reflectivity and allows the land and oceans to absorb more heat. More water vapor entering the atmosphere traps more heat. And now clouds are another concern.

Overall, these effects are leading to climate models predicting much larger global temperature increases, which is a scary prospect for the world.

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Why Clouds Are the Key to New Troubling Projections on Warming

Photo, posted September 10, 2006, courtesy of Nicholas A. Tonelli via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Arguing Against Climate Change

April 3, 2017 By EarthWise

Most of the world has accepted the analysis of the overwhelming majority of climate scientists that shows that our planet is warming and that our actions are the primary cause. However, some people – notably a number holding high office – reject this analysis. What exactly does it imply to say that climate change is not happening or is not caused by us?

Disappearing Arctic Ice

October 25, 2016 By WAMC WEB

The top of the world is turning from white to blue in the summer. The ice that has long covered the north polar seas is melting away.