4. If the Earth were to warm by 3 degrees, by how much would sea levels rise?

The rise in sea levels due to a 3-degree Celsius increase in global temperatures is not a simple 1:1 calculation because it depends on a multitude of factors, including the rate of ice melt at the poles, thermal expansion of seawater, and regional differences affected by ocean currents and geography.

Generally, research indicates that a 3-degree Celsius rise in global average temperature could eventually lead to a sea-level rise in the range of several meters over time. This process, however, is not instantaneous. It could take centuries for the full effects on sea levels to be realized because of the time it takes for ice sheets to melt and for the ocean to warm and expand.

One long-term study projection suggests that each degree Celsius of global warming could ultimately raise sea levels by roughly 2.3 meters over the course of 2,000 years. But this again is a long-term effect. More immediate predictions for sea-level rise by the end of this century, assuming significant warming, range from about half a meter to a meter or more, depending on greenhouse gas emissions and melting processes.