Throughout Earth history, climate has constantly changed. But current climate change is occurring much faster and on a much grander scale than at any time in our planet’s history. Scientists agree that this rapid and widespread warming is mainly due to human activities, particularly burning fossil fuels like oil, natural gas and coal. These fuels release gases into the atmosphere that trap heat from the sun, warming Earth’s surface. The planet is also becoming warmer due to a reduction in snow and ice.
Climate change is impacting people in every corner of the world — from food insecurity to loss of livelihoods, from rising sea levels to longer and more intense droughts. It is also affecting wildlife from polar bears in the Arctic to marine turtles off Africa. And of course, climate change is a threat to the health of all living things.
For example, a warmer world means that diseases carried by insects will flourish. And more extreme weather events like droughts and floods are causing damage and displacement, with some estimates suggesting that the number of climate change-related refugees could reach 60 million by 2050.
We know more than ever about what is causing climate change, and how it might impact us. But it’s still hard to determine the exact impacts in our local communities. In the past, scientists have been able to make these calculations using models based on observations and information from natural processes, such as variations in solar radiation and wind patterns. But we have much more data now, from Earth-observing satellites that give a planet-wide perspective of global temperatures.
These satellites have shown, for instance, that the rate of warming has been accelerating over the past few decades as ocean currents bring heat stored in the deep ocean to the surface. They have also spotted that glaciers are melting quickly, and that the ice sheets of Greenland and Antarctica are shrinking at an alarming rate.
Scientists believe that if we are able to reduce our emissions dramatically, we can limit the global temperature rise to 2 degrees Celsius, and even 1.5 degrees Celsius. But if we continue on our present path, the rise is likely to be higher than that. And that will have profound consequences for humankind and all living creatures, especially those in the poorest countries.