The climate system is an interconnected web of interacting physical, chemical and biological processes. Its overall state is determined by a delicate balance of incoming solar energy (radiation) and outgoing energy in the form of long-wave radiation emitted back into space. This process is altered by human activities, especially the burning of fossil fuels, which releases heat-trapping greenhouse gases into the atmosphere. These gases alter the Earth’s energy balance, with a consequential increase in the average surface temperature of the planet.
As global temperatures rise, they impact many aspects of life on Earth, from increasing frequency and intensity of heat waves to melting ice sheets, ocean warming and changes in rainfall patterns that lead to droughts or floods. The impacts are already being felt.
Scientists say that, without significant action, the world is on track to warm by at least 2°C above pre-industrial levels. This warmer scenario could trigger major planetary tipping points, such as the collapse of the Greenland Ice Sheet or further loss of the Amazon rainforest.
All countries, peoples and ecosystems are affected by climate change. But the poorest nations, which have contributed least to the problem, tend to be on the front lines of climate impacts. This is because they lack the resources to adapt and depend heavily on a healthy, functioning natural world for their livelihoods.