Could the world be self healing?

17 May 2016

Question

I accept that global warming is an known fact and that the answer is a reduction in greenhouse gases and that as a result of the increase of such gases there will be an ever increasing incidence of environmental thermo dynamic meteorological activity across the globe and that the ball is in our court to take positive steps to manage the problem.

My question is: How much will this increased activity, more storms, more wind etc, contribute to a "self healing" effect. In other words will increased environmental activity of itself reduce the CO2 in the atmosphere.

Answer

We asked oceanographer Dan Jones to answer this question...

Dan - At the moment we do have some amount of the carbon dioxide that we put into the atmosphere does go into the ocean. It's roughly 20% of the amount that we emit is absorbed by the ocean and the other 30% roughly goes into the land and the other about less than half stays in the atmosphere. The term that you'll see thrown around is sinks of carbon dioxide. There's the oceanic sink and the land-based sink.

So the question is: can these sinks continue to do that job into the future? It's a big area of research right now and there's a ton of people working on it and a lot of effort going into this. so it's a really interesting question. I'd be careful about making too many summary statements just at the the moment but yes, it's a good question and there's a lot of work going into this.

Chris - We have evidence that this has happened in the past, haven't we? Because, for instance, we know that the Himalayas were formed when India, which was down near Antarctica, has migrated up across the Indian Ocean and it's pushed up the sea floor in front of it and made the Himalayas that way. Exposed lots of minerals from the sea floor and that's pulled carbon dioxide down out of the atmosphere and that triggered the ice age, didn't it?

Dan - Right. So these are very long term sinks of carbon dioxide. This is a geological one and these long term sinks take many thousands. ten thousand years, that kind of timescale to actually bring the carbon dioxide in the atmosphere down or back up, depending on which way that feedback mechanism is operating, so they're much, much slower.

The concern is that right now we're putting carbon dioxide into the atmosphere much faster than any of these natural sinks can get it back down very quickly. For example, that over the past million years we've seen 4-7 degree celsius temperature variations and these temperature variations are associated with these long sinks that you're referring to. But, usually, that temperature change of 4-7 degrees, those usually happen over about 5,000 year periods of time whereas right now in the past century, we've seen about a 0.7 degree celsius rise, which is ten times faster than the ice age recovery warming.

Chris - So you're saying that although we're seeing small changes in temperature, they're occurring over shorter timescales so, actually, the rate of change is much greater than we've seen in long timescales before?

Dan - That's the concern, yes.

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