Global temperatures are projected to rise by 1.9-3.7°C by the year 2100

Current policies of governments around the world are likely to result in global warming of between 1.9 and 3.7°C by 2100, with potentially more to come in the 22nd century.

“Each year, 2,100 people continue to emit more CO2 as global temperatures rise,” said Zeke Hausfather, a climate scientist at Stripe, a California-based software company that invests in carbon removal technologies. states.

His conclusions are based on a review of more than a dozen studies published over the past five years, looking at the implications of current policies over the past five years. According to these studies, the world is most likely to warm between 2.3 and 3°C by 2100.

However, these numbers do not fully take into account the uncertainties about future emissions of greenhouse gases as a result of human actions and how the climate system will respond to those emissions. Including these uncertainties gives a wider range of 1.9–3.7 °C.

These numbers reflect the most likely range of scenarios from the 5th to 95th percentile. This means that even with current policies, there is a small chance of a maximum warming of 4.4°C this century.

The good news is that all recent studies agree that very high emissions scenarios are currently unlikely. For these, warming of 4°C or more before 2100 is the most likely outcome.

That's because the worst-case scenarios considered by climate scientists were never all that plausible to begin with, Hausfather says, but it also reflects real progress in limiting emissions growth. and coal is currently expensive.

If climate policies strengthen and technological advances continue to exceed expectations, future emissions could be even lower than assumed in these studies, but this is not guaranteed and The rise of energy-hungry technologies like intelligence could do the opposite.

“It's definitely possible to imagine a world where AI accelerates rapidly and near-term emissions increase beyond what we think will happen today,” Hausfather says.

But he doesn’t think AI-related emissions will make much of a difference in the long term. “It’s certainly not in line with rapid emissions reductions, but it’s hard to see that in itself putting us on track for a significantly different end-of-the-century outcome,” Hausfather says. .