Possible solutions ...

    Countries around the world acknowledged the imperative to act on climate change with the Paris Agreement in 2015, making pledges to reduce greenhouse gas pollution. The Intergovernmental Panel on Climate Change (IPCC), which synthesizes the scientific consensus on the issue, has set a goal of keeping warming under 2 degrees Celsius (3.6 Fahrenheit) and pursuing an even lower warming cap of 1.5 degrees Celsius (2.7 Fahrenheit).

   Addressing climate change will require many solutions—there's no magic bullet. Yet nearly all of these solutions exist today, and many of them hinge on humans changing the way we behave, shifting the way we make and consume energy. The required changes span technologies, behaviors, and policies that encourage less waste and smarter use of our resources. For example, improvements to energy efficiency and vehicle fuel economy, increases in wind and solar power, biofuels from organic waste, setting a price on carbon, and protecting forests are all potent ways to reduce the amount of carbon dioxide and other gases trapping heat on the planet.

     Scientists are also working on ways to sustainably produce hydrogen, most of which is currently derived from natural gas, to feed zero-emission fuel cells for transportation and electricity. Other efforts are aimed at building better batteries to store renewable energy; engineering a smarter electric grid; and capturing carbon dioxide from power plants and other sources with the goal of storing it underground or turning it into valuable products such as gasoline. Some people argue that nuclear power despite concerns over safety, water use, and toxic waste should also be part of the solution, because nuclear plants don't contribute any direct air pollution while operating.

    While halting new greenhouse gas emissions is critical, scientists have also emphasized that we need to extract existing carbon dioxide from the atmosphere. More fanciful ideas for cooling the planet—so-called “geoengineering” schemes such as spraying sunlight-reflecting aerosols into the air or blocking the sun with a giant space mirror—have largely been dismissed because they may pose more environmental risks than proven benefits.