The urgency of action on climate change is a complicated thing. On the one hand, the harm of inaction is real and growing every year. On the other hand, there’s no such thing as “too late.” Plug in some numbers, and you can define a corresponding deadline to hit a target, but we’re not dealing with an all-or-nothing proposition. There is a continuum of consequences, and our choices can always move us one notch toward “better” or one toward “worse.”

With that in mind, the latest report from the Intergovernmental Panel on Climate Change (IPCC) shows the next few years are a critical window of opportunity for our hopes of limiting global warming to the benchmarks of 1.5° C or 2° C. Those numbers aren’t magic, but they are meaningful. First, they represent better futures than any larger number on the thermometer would. Second, these are the targets that international negotiations have long centered around.

(Giga)tons of work to do