Global warming is a long-term rise in the average temperature of the Earth's climate system. It is a major aspect of climate change, and has been demonstrated by direct temperature measurements and by measurements of various effects of the warming.

In recent years, scientists have noticed a rapid melting of the polar ice caps. This phenomenon, which they call "rapid glacial retreat", threatens coastal cities worldwide due to rising sea levels.

Line 4: "The primary driver of this recent warming is the emission of greenhouse gases by human activities." This highlights the urgent need for renewable energy adoption.