CBS News, along with more than 250 news outlets worldwide, is participating in the Covering Climate Now project, a joint initiative founded by the Columbia Journalism Review and The Nation magazine. CBS News will be devoting this week to covering climate change from all angles across all our platforms — broadcast and digital — leading up to the United Nations Climate Action Summit in New York on September 23. "Face the Nation" kicked off a special Eye On Earth series Sunday.

Here are five things to know about climate change — and its impact on the world already:

1. Weather

More and more countries around the world are experiencing record high temperatures, droughts, unprecedented floods and other extreme weather events.

According to NASA, the average global temperature has increased by .8 degrees Celsius with 18 of the 19 warmest years occurring since 2001.

The U.N. has warned if the average global temperature increases by 2 degrees Celsius there could be massive sea level rise and almost all the world's coral reefs could die.

2. Food Security

Increasing temperatures are already affecting agricultural productivity, putting fruit and vegetable supplies at risk. Unpredictable precipitation patterns and more frequent extreme weather events are adding to disruptions in the food system. Farmers in the U.S. have already felt the harsh outcomes of droughts and unprecedented flooding.

3. Water

Countries around the world are starting to experience stress on their water supply. The World Resources Institute found that 17 countries are currently under extremely high water stress, which is when the demand for water exceeds the available amount or poor quality restricts its use. Twelve out of those 17 countries are in the Middle East and North Africa.

What's contributing to this global water crisis?

Population growth, socioeconomic development and urbanization are increasing water demands, while climate change is causing unpredictable precipitation levels and demand.

Last year, Cape Town, South Africa, narrowly avoided a "day zero" when the city's water supply was expected to run out.

4. Economy

A government report released November 2019 warned that a warmer planet could mean a big hit to G.D.P. in the coming decades.

The report, issued by 13 federal agencies, predicts that if significant steps are not taken to rein in global warming, the damage will knock as much as 10 percent off the size of the American economy by century's end.

5. What are world leaders doing about it?

In 2016, 174 countries and the European Union signed onto the U.N. Paris Agreement, which aims to prevent global temperatures from rising 2 degrees Celsius through "nationally determined contributions."

But the U.N. notes the agreement itself is meaningless without ambitious action from each nation.

President Trump left the agreement in 2017, laying the groundwork for the Trump administration's environmental deregulation policies.

Mr. Trump said he isn't convinced by the science around climate change, expressing skepticism that it's man-made.