Beyond the Data

Climate evidence is robust about what has happened and why. It is less certain about exactly what will happen, because future warming depends on human choices about emissions, which no model can predict precisely.

Projections span scenarios from aggressive emission cuts to business as usual. Under the best ones, warming stabilizes around 1.5 to 2 degrees Celsius; under the worst, it exceeds 4 degrees by 2100. The uncertainty is not a reason for inaction. It is a reason for urgency.