Caldeira Lab

Greenhouse gases, climate change, and the transition from coal to low-carbon electricity: Ken Caldeira

Click here to read about the paper



Nathan Myhrvold of Intellectual Ventures came to me with an idea for a scientific paper, which was something unusual.

The question that he wanted to address is how much cooling benefit or warming avoided would we get by transitioning from a coal-based electricity generation system to lower carbon emission systems. So we constructed a very simple climate model with a simple ocean and another model representing the radiation balance or energy balance of the earth. Then we represented different energy technologies by how much greenhouse gases were emitted during the construction of these power plants and how much greenhouse gases were releases during the operation of these power plants. And then we looked at transitions from a coal-based power plant to this new lower carbon emission power plants.

What we found was two basic things:

That in order to get substantial climate benefit, you really need to go to the very low carbon emission energy technologies that if you, say, take something like natural gas that it does have less emissions than coal and so it does have less of climate change. But you can think of it as you’re delaying the time to get to the same amount of climate damage. And if you want to avoid that damage, you really have to go to low-emission systems.

The other thing is the flipside of how long it takes for us to feel the effects of our emissions that if we emit CO2 to the atmosphere, it takes around 40 years before we get the full amount of warming from that. And conversely, if we avoid a CO2 emission, it takes around 40 years before we feel the full benefit of that. And so the emissions reductions that we put in place in the first half of the century we’re going to benefit from primarily in the second half of the century.

So the two real take-home messages from our study is that, in order to get significant climate benefit, we really need to move to the lowest carbon emission energy technologies, but even in that case it’s going to take until the second half of this century before we experience most of the benefit.

Myhrvold, N.P., and K. Caldeira, 2012. Greenhouse gases, climate change, and the transition from coal to low-carbon electricity. Environmental Research Letters, Vol. 7, 014019 doi:10.1088/1748-9326/7/1/014019. 2012.

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