Wednesday, August 15, 2018

They Don't Actually Run Away. They Sort Of Crawl. The A,B,C's of Natural Feedback Loops.

Back in ancient times, 15-20 years ago, we were warned that, unless we abandoned fossil fuels and damned smartly, somewhere toward the end of this century we might just trigger these natural feedback loops, tipping points, the advent of runaway global warming.

It turns out those scientists were hedging their bets. Hey, we've never gone through something that's coming to look a bit like an extinction event, so how were they to know? It's all water under the bridge at this point.

Two recent reports (here and here) indicate that global warming/climate change is no longer mankind's exclusive preserve. Nature is now also at work.

In my experience, most people have only a vague and sometimes inaccurate understanding of these feedback loops or tipping events. So here, from The Guardian, are a few helpful A,B,Cs.

By feedbacks, we mean a change in one part of the climate that then causes another change, which in turn may cause another change, and so on, potentially setting up chain reactions.

For example, melting ice is one feedback, particularly in the Arctic. Humans have emitted greenhouse gases that have caused the Earth to warm. As the Earth warms, ice melts; as ice melts, it means there is less white reflective cover on the Earth surface. In fact, a lot of this ice melting is happening in the Arctic. Instead of having a white surface that reflects sunlight, we have open ocean water that absorbs sunlight.

...Activating one of these cycles is bad news for a few reasons. First, it takes away a lot of control of the Earth’s climate from us. Right now, humans control the climate through our emissions of greenhouse gases. But once these cycles get activated, the Earth’s climate will partially control itself. That means it will be harder to stop the warming process.
Then there are the knock-on effects, where one feedback loop may trigger or amplify others.  For example the warming Arctic air melts the permafrost that then releases the methane that has been sequestered in it for hundreds of thousands, possibly millions of years. That methane, a powerful greenhouse gas, emits to the atmosphere where it adds to all the man-made greenhouse gases to speed up the warming. A warmer atmosphere increases evaporation and, at the same time, increases the atmosphere's ability to hold water vapour. Then you get a warmer, wetter atmosphere that provides the fuel for a variety of severe weather events - tornadoes, hurricanes, once-a-century floods. It also messes up the jet stream.

Eventually you get to chart all the changes:

But the term, "runaway global warming," is a bit alarmist.  Some of these feedback loops will come online sooner than others. Also this is not a linear process. Some may occur in fits and starts. Some changes may be large and abrupt followed by a period of dormancy.  Some of these changes, such as the loss of the Antarctic ice sheets will continue over a period of centuries (or so we hope.)

Unfortunately the way our leaders - pretty much the lot of them - are addressing these tipping points, natural feedback loops, is to not address them. That would be a tacit admission of failure to act on man-made emissions when they had the opportunity to really make a difference.

The Petro-Pimps of Parliament Hill and their provincial counterparts can't even agree how to take the first baby step on emissions, carbon pricing. They'll be screwing around with that for years, burning up time we don't have to waste. Meanwhile the Dauphin, while pushing carbon pricing, will be doing everything in his power, no tax dollar spared, to flood the world markets with the filthiest, most toxic and highest-carbon ersatz petroleum on the planet, bitumen.

With leaders of the calibre of Canada's political caste, consider yourself buggered.

1 comment:

Anonymous said...

It should be pointed out that feedback loops can be positive (e.g., in simple terms, climate warming results in events that cause more climate warming) or negative (e.g., again in simple terms, climate warming results in events that cause less warming). The examples given are positive feedback loops. I don't know of any negative feedback loops with regards to climate warming, but there might be some.

Politicians are afraid to take action because it will cost money and/or people might lose their jobs, and this would result in politicians not getting re-elected, which is far worse than potential extinction (tongue in cheek).