Average air temperatures are rising. Climate change has already increased average temperatures enough to shift seasons — spring comes earlier and fall frosts arrive later. While average global air temperatures are warming, historical data also reflects that we are also experiencing more extreme temperature change.
Modern climate change differs from natural climate change — also known as geologic climate change — because it is caused by humans and is occurring much faster than geologic climate change. Modern climate change is primarily driven by the effects of greenhouse gases, and is directly linked with human activities.
A jump from 1.5 to 2 degrees—a third more of an increase—raises projected impacts by about that same fraction, and this is a big deal. Heat waves would last around a third longer, rain storms would be about a third more intense, the increase in sea level would be approximately that much higher and the percentage of tropical coral reefs at risk of severe degradation would be roughly that much greater.