On the whole, a lot of people agree that something needs to be done to stop global warming. Whether they believe it is happening or not, is sometimes not the issue; simply in case it is happening is enough to warrant action, many believe. Governments are debating what to do, NPO’s are telling them what to do, and we – the lowly reporters – are telling you what they’re all thinking, and why.
But none of it may matter, according to new research published in the January 15 edition of the journal Geophysical Research Letters, which states that even if all emissions of greenhouse gasses abruptly stopped right …
…planet Earth could still keep warming.
The new research shows that even if emissions were stopped now, temperatures would remain higher than they were during the pre-Industrial Revolution as a result of all the emissions that have already been released into the atmosphere.
Because those emissions are likely to hang around for thousands of years, whereas the few aerosols that are emitted into the atmosphere which can reflect sunlight back, will only last a few weeks if they are not replenished.
In fact, it is possible temperatures would continue to escalate even if all cars, heating and cooling systems and other sources of greenhouse gases were suddenly eliminated, said Kyle Armour, a doctoral student in physics at the University of Washington. “The aerosols would wash out quickly and then we would see an abrupt rise in temperatures over several decades.”
Armour, along with co-author Gerard Roe, an associate professor of Earth and Space Sciences at the University of Washington, analysed and calculated the observed warming, as well as the known levels of greenhouse gases and aerosols already in the atmosphere, to gauge what might happen if all emissions suddenly ceased.
In the best-case scenario, the global temperature would actually decline, but it would remain about a half-degree F higher than pre-Industrial Revolution levels and probably would not drop to those levels again, Armour said.
That’s the best-case scenario though.
There is the possibility that temperatures would continue to rise another 3.5 degrees Fahrenheit higher than before the Industrial Revolution, a threshold which scientists have already set aside as a point at which significant climate-related damage could begin to occur.
Uncertainties abound in this study, the largest being the needed catastrophic event which could cease all greenhouse gas emissions. But Armour also notes that the uncertainties surrounding the overall effect of aerosols is one that should not lessen the importance of the findings. Armour and Roe are confident that some warming would have to take place even if all emissions ceased.
As emissions of greenhouse gases continue, the “climate commitment” to a warmer planet only goes up, Armour said. He believes it is helpful for policy makers to understand that level of commitment. It also will be helpful for them to understand that, while some warming is assured, uncertainties in current climate observations – such as the full effect of aerosols – mean the warming could be greater than models suggest.
“This is not an argument to say we should keep emitting aerosols,” he said. “It is an argument that we should be smart in how we stop emitting. And it’s a call to action because we know the warming we are committed to from what we have emitted already and the longer we keep emitting the worse it gets.”