Thread by @AlexSteffen

Here's the biggest problem with explaining the need for climate action with carbon budgets: In my experience, many people react to them as if they are the budget we get to "spend" before we are going to be forced to act on climate.

1/

The reality, of course, is that carbon budgets are [controversial] estimates of the total greenhouse gas pollution we can emit before losing a given chance of holding temperatures at a given level (for instance, a 66% chance of holding warming to 2ºC).

2.

Here's the thing, though: Getting off fossil fuels, closing our economy into sustainable loops, ruggedizing for the impacts ahead, spreading sustainable development—all of these, in our current economy, mean emitting carbon.

We can't get off carbon without burning carbon.

3.

Since burning the carbon to get off carbon is unavoidable, the pollution demanded to transform our society needs to be given precedence in the budget.

If we can only "spend" X gigatonnes of CO2, we'd better make sure we include all the pollution we'll emit as we get to zero.

4.

The problem is, it looks pretty clear that retooling civilization to be zero-carbon and rugged will, in all but the most aggressive/optimistic approaches, use up a huge portion of any sensible target's climate budget—maybe even all of it.

5.

In other words, we should be "spending" every tonne of CO2 we emit on reducing emissions.

There is no "extra" for continuing business as usual, much less any for building new high-carbon systems (from coal plants to highways).

6.

We should not be building any new high-carbon systems anywhere in the world, for anything... with a handful of arguable exceptions in the poorest nations on humanitarian grounds.

7.

In rich countries, no new sources of climate emissions are compatible with realistic climate policy, or morality.

The continuation of high-carbon systems aren't compatible either.

8.

So every time we hear "carbon budget" we should not think "the runway we have before we have to change" but "the target that tells us that time's up, now."

9.