We need to rethink everything we know about global warming

We need to rethink everything we know about global warming

SOURCE: Science Daily DATE: January 22, 2019 SNIP: For a while now, the scientific community has known that global warming is caused by human made emissions in the form of greenhouse gases and global cooling by air pollution in the form of aerosols. However, new research published in Science by Hebrew University of Jerusalem Professor Daniel Rosenfeld shows that the degree to which aerosols cool the earth has been grossly underestimated, necessitating a recalculation of climate change models to more accurately predict the pace of global warming. To what extent do aerosols cool down our environment? To date, all estimates were unreliable because it was impossible to separate the effects of rising winds which create the clouds, from the effects of aerosols which determine their composition. Until now. With this new method, Rosenfeld and his colleagues were able to more accurately calculate aerosols’ cooling effects on the Earth’s energy budget. And, they discovered that aerosols’ cooling effect is nearly twice higher than previously thought. However, if this is true then how come the earth is getting warmer, not cooler? For all of the global attention on climate warming, aerosol pollution rates from vehicles, agriculture and power plants is still very high. For Rosenfeld, this discrepancy might point to an ever deeper and more troubling reality. “If the aerosols indeed cause a greater cooling effect than previously estimated, then the warming effect of the greenhouse gases has also been larger than we thought, enabling greenhouse gas emissions to overcome the cooling effect of aerosols and points to a greater amount of global warming than we previously thought,” he shared. The...
Pollution is slowing the melting of Arctic sea ice, for now

Pollution is slowing the melting of Arctic sea ice, for now

SOURCE: The Guardian DATE: August 3, 2018 SNIP: The Arctic is one of the “canaries in the coal mine” for climate change. Long ago, scientists predicted it would warm quicker than other parts of the planet, and they were right. Currently, the Arctic is among the fastest-warming places on the planet. Part of the reason is that as the Arctic warms, ice melts and ocean water is uncovered. The ocean is darker than ice so it in turn absorbs more sunlight and increases its warming. This is a feedback loop. Humans emit greenhouse gases that trap heat. We know that and we have known that for a long time. Greenhouse gases make the Arctic warmer. But, other things are happening too. There are natural changes to the Arctic. There are also other human pollutants that affect the ice. For instance, humans emit small particles called “aerosols” that can get into the atmosphere and block sunlight. So, these human aerosol emissions can actually cause cooling. The authors concluded that the combined cooling effect from human aerosols was detected in all three datasets of ice. That means, it didn’t matter whose measurements you used – the effect of aerosol cooling was present. So how much of an effect do aerosols have? It turns out 23% of the warming caused by greenhouse gases was offset by the cooling from aerosols. Unfortunately, this isn’t good news. It means that if/when humans reduce our aerosol pollution, the warming in the Arctic and the ice loss there will be worse. This puts us into a Faustian bargain. We want to reduce airborne pollution, like sulfur...