climate is a significant and lasting change in the statistical distribution of weather patterns over periods ranging from decades to millions of years. It may be a change in average weather conditions or the distribution of events around that average more or fewer extreme weather events. Climate change may be limited to a specific region or may occur across the whole Earth.
On the broadest scale, the rate at which energy is received from the sun and the rate at which it is lost to space determine the equilibrium temperature and climate of Earth. This energy is then distributed around the globe by winds, ocean currents, and other mechanisms to affect the climates of different regions.
The challenge of preventing climate change is formidable but not insurmountable. To avoid a dangerous level of climate change, defined by the European Union (EU) as an increase in the global mean surface temperature of 2°C or more above pre-industrial levels, developed countries will be required to stabilise and then cut their current greenhouse gas (GHG) emissions between 60 and 80 percent by 2050. Developing countries will have to stabilise their emissions while finding new, low carbon pathways to development. Timing is also critical: the longer action is delayed the steeper the reduction track will become and the harder climate change will be to manage.