Scientists made a detailed “roadmap” for meeting the Paris climate goals. It’s eye-opening
Back in 2015, the world’s governments met in Paris and agreed to keep global warming below 2°C, to avoid the worst risks of a hotter planet. See here for background on why, but that’s the goal. For context, the planet’s warmed ~1°C since the 19th century.
One problem with framing the goal this way, though, is that it’s maddeningly abstract. What does staying below 2°C entail? Papers on this topic usually drone on about a “carbon budget” — the total amount of CO2 humans can emit this century before we likely bust past 2°C — and then debate how to divvy up that budget among nations. There’s math involved. It’s eye-glazing, and hard to translate into actual policy. It’s also a long-term goal, easy for policymakers to shrug off.
So, not surprisingly, countries have thus far responded by putting forward a welter of vague pledges on curbing emissions that are hard to compare and definitely don’t add up to staying below 2°C. Everyone agrees more is needed, but there’s lots of uncertainty as to what “more” means. Few people grasp how radically — or how quickly — we’d have to revamp the global economy to meet the Paris climate goals.
Surely there’s a better, more concrete way to think about this. So, in a new paper for Science, a group of European researchers try to do just that — laying out in vivid detail what would have to happen in each of the next three decades if we want to stay well below 2°C. Fair warning: It’s unsettling.
A simple (but daunting!) road map for staying below 2°C
They start with the big picture: To hit the Paris climate goals without geoengineering, the world has to do three broad (and incredibly ambitious) things:
1) Global CO2 emissions from energy and industry have to fall in half each decade. That is, in the 2020s, the world cuts emissions in half. Then we do it again in the 2030s. Then we do it again in the 2040s. They dub this a “carbon law.” Lead author Johan Rockström told me they were thinking of an analogy to Moore’s law for transistors; we’ll see why.
2) Net emissions from land use — i.e., from agriculture and deforestation — have to fall steadily to zero by 2050. This would need to happen even as the world population grows and we’re feeding ever more people.
3) Technologies to suck carbon dioxide out of the atmosphere have to start scaling up massively, until we’re artificially pulling 5 gigatons of CO2 per year out of the atmosphere by 2050 — nearly double what all the world’s trees and soils already do.
See more here.
