What is Climate Change ?

Observed changes over the 20th century include increases in global air and ocean temperature, rising global sea levels, long-term sustained widespread reduction of snow and ice cover, and changes in atmospheric and ocean circulation as well as regional weather patterns, which influence seasonal rainfall conditions. These changes are caused by extra heat in the climate system due to the addition of greenhouse gases to the atmosphere. These additional greenhouse gases are primarily input by human activities such as the burning of fossil fuels (coal, oil, and natural gas), deforestation, agriculture, and land-use changes. These activities increase the amount of ‘heat-trapping’ greenhouse gases in the atmosphere. The pattern of observed changes in the climate system is consistent with an increased greenhouse effect. Other climatic influences such as volcanoes, the sun and natural variability cannot alone explain the timing and extent of the observed changes.

Climate, refers to the long-term regional or global average of temperature, humidity and rainfall patterns over seasons, years or decades.

While the weather can change in just a few hours, climate changes over longer time frames. Climate change is the significant variation of average weather conditions becoming, for example, warmer, wetter, or drier – over several decades or longer. It is the longer-term trend that differentiates climate change from natural weather variability. 

As the planet continues to warm, climate patterns change. Extreme and unpredictable weather will become more common across the world as climate patterns change, with some places being hotter, some places being wetter, and some places being drier. These changes can have – and are already having – drastic impacts on all life on the planet.