Today we talk about tipping points, two in particular.
The basic story line of climate change concerns the carbon humanity puts into the atmosphere through fossil fuels. This is carbon that was sequestered in oil, gas and coal for millions of years which has been suddenly added to the climate system through human action. As greenhouse gases, this carbon decade by decade captures ever more energy from the sun and raises the temperature of the planet around us.
Tipping points are a second but equally important part of the story. Tipping points refer to secondary processes which the carbon puts in motion. If we envision climate change as a slowly starting avalanche, then we see that after awhile carbon dioxide is not the only pebble rolling down the hill.
Two other pebbles in this avalanche, two climate tipping points which I want to discuss here, are related to the Arctic. One has to do with albedo. The other has to do with permafrost.
Permafrost refers to areas of exposed soil where the temperature has remained below freezing for a year or more. 24% of the soils in the far north fit into this category. Permafrost is also found in elevated areas, in the southern tip of South America, and other similarly cold places.
Worldwide, permafrost sequesters an estimated 1.5 trillion tons of carbon—in the form of methane and other hydrocarbons—twice the amount of carbon that is presently in the atmosphere.
Just to get some perspective, as a greenhouse gas methane is 25 times more effective than CO2. The release of large amounts of methane into the atmosphere would thus not be good news in an era when global climate is already heating up an order of magnitude faster than it ever has before.
That’s among the reasons why we prefer to leave the carbon in the soil, and why we prefer that permafrost remain permanent.
Unfortunately, the way climate change is unfolding is not really helping us to keep it that way.
For one thing, climate change affects the polar regions more than the equatorial regions.
You go into a cold room, you feel a chill. That’s because heat is flowing out of you faster in the cold room. The planet works roughly the same way. The added heat of global warming flows faster into the colder regions than into the warmer.
There are differences between the poles too, because the conditions are different north and south. The Arctic doesn’t have a high plateau with a continental ice sheet perched on it to keep temperatures stable like Antarctica does, nor does it have an ozone hole to mess up the climactic equations further. What the Arctic does have are seas, and this fact is related to something else which scientists have been trying to explain.
You see, the Arctic is actually warming much faster than predicted. The why of this, as they have recently realized, is that most of the warming now occurring in the Arctic is no longer the direct result of CO2. It is in fact deriving from the changing albedo of the Arctic waters.
You know what albedo is. It’s the reason why, if you want to fight the heat, you wear light-coloured clothing on a steaming hot day rather than dark. Light coloured clothing, as everybody knows, reflects heat while dark coloured absorbs it.
The albedo of the Arctic seas has changed because large parts of these seas which used to be covered with ice year round no longer are. Thus heat that used to be reflected back into space by a reflective sea ice cover is now being absorbed by the dark open waters which the shrinking ice has exposed. And these waters, taking in more heat than usual and so being warmer than usual, are assisting the ice floating in them to melt even faster.
The bottom line is that the process of warming in the Arctic has now passed beyond CO2. It has gone over an internal tipping point. What this means is that , although CO2 continues to contribute to the equation, the ongoing warming in the Arctic is now fundamentally internally powered.
That means to fight warming in the Arctic, we have to do two things instead of one. First—what we had to do all along—we have to reverse the effects of the CO2 that we’ve put into the atmosphere. Secondly—and this is the poison pill of delaying our action on climate change—we have to reverse the effect of the open, ice-free Arctic seas.
Good luck, Sam, with re-icing them.
Okay, let’s say that, like our denier friend Simple Sam, you don’t care about a warming Arctic.
You see a polar bear floating by on an ice floe, you’re not like some lefty softy who says, “Aw, polar bear. Hope it doesn’t drown.”
But let’s get back to the permafrost. Permafrost exists because the places where it is found are cold, and have been cold for a long time.
Like the Arctic.
Like the Arctic which is warming faster than anybody predicted because of something we forgot to watch out for. Albedo.
Albedo, tipping point number one, speeding us to tipping point number two, defrosting permafrost.
If just a small percentage of the permafrost in the lands surrounding the Arctic seas begins to release methane, it could accelerate global warming significantly. And that accelerated warming would defrost even more permafrost and release even more methane.
Another self-fueling tipping point will have been passed. Another pebble dislodging further pebbles.
To reverse the second tipping point we’ll have to go back and refrost the Arctic. Something we’ll get to, I guess, right after we’ve restored the ice cover on the Arctic seas.
We’ll have so much fun with that project.
Maybe the climate change deniers have a solution to it which they’ve so far left out of their discussions.
I mean, other than the obvious one.
Changing our way of doing things. Moving to alternative forms of energy. Getting to work and using a little sweat and a touch of our human genius to find solutions to all these things.
Actually doing something, starting now. Not just hiding our heads in the sand as our denier brothers counsel us to do.
It doesn’t take a whole lot of insight to realize that there’s a time limit to reversing avalanches.