These 20 images of Earth over the past 70 years show why countries signed the Paris Agreement

President Trump is expected to announce a US withdrawal from the landmark Paris Agreement on Thursday afternoon. The international accord, which was signed by every country except Nicaragua and Syria, lays out a framework for countries to reduce their fossil fuel emissions in order to keep the planet's overall temperature from rising more than 2 degrees Celsius.

Since the industrial revolution, humans have had an unmistakable impact on Earth - one that has accelerated over time. This impact pops out in sharp relief when you look at this collection of images comparing what specific areas look like now to how they appeared roughly 70 years ago.

In some cases, the images (mostly from NASA, unless otherwise noted) were taken as far as 50 years apart; in other cases, they were snapped with just 10-15 years in between.