I wasn't convinced by this bit:

> When I first heard this I was surprised. Can’t we just aim to cut carbon emissions in half? I asked many scientists. But they all agreed that wouldn’t be enough. The problem is that CO2 lingers in the atmosphere for decades. Even if we halted carbon emissions tomorrow, the temperature would still rise because of the carbon that’s already been released. No, we need to get all the way down to zero.

So if we can only reduce them by 99%, we shouldn't even bother?

It seems to me that the closer we get to zero, the more expensive the next 1% will be. At some point, it's not worth the cost to keep going, and we'd be better off looking for ways to remove some of the CO2 that's in the atmosphere instead of just reducing how much we're pumping in. His equation notably omits that possibility.

I think they're really talking about opportunity costs. Dollars spent on making oil-burning engines more efficient are dollars not spent on developing technologies to replace oil-burning engines, and replace is really what we need.

Dollars spent on making oil-burning engines more efficient might repay themselves very quickly, making this not a trade-off, but an `why not both'?

but it is just ignorant that efficiency gains aren't paying off. The number of miles driven versus the fuel cost to do so quickly and absolutely justifies the efficiency gains of the past three decades. There is no reason to not think this won't carry forward.

Yes there are many opportunities in replacement but none have won out and more are on their way. None are at a price point where those least capable of the costs are going to be able to take advantage of them. So in that meantime we keep pushing the cost of burning fossil fuels down.

There is likely an efficient (in the economic sense of the word) level of CO2 emissions, but I doubt that anyone knows what it is. It's very difficult to price. However, I do agree with you that it's probably not zero.

The good news is that we have a proven carbon capture technology. Grow new forests.

Forests aren't sustainable unless you're also logging them and storing the wood permanently somewhere. They also consume valuable fertile land so it's not necessarily a worthwhile method. Perhaps in some post-oil economy they would become economical.