Global warming refers to the recent (pre-industrial to present) temperature increase of the earth’s surface and lower atmosphere. In order to keep the negative consequences of global warming under control, the average global temperature rise should be limited to less than 2˚C relative to the pre-industrial level – as was agreed at the United Nations Framework Conference on Climate Change (UNFCCC). Beyond that limit, climate change becomes catastrophic and irreversible.
Scientists are more than 90% sure that global warming is primarily caused by increasing concentrations of greenhouse gases and CO2 emitted by human activities. The mass burning of fossil fuels such as oil and coal, cutting down rainforests (deforestation) and farming livestock adds enormous amounts of GHGs to our atmosphere, increasing the greenhouse effect and global warming. As a consequence, Global temperatures will rise significantly, as will sea levels. We should expect extreme weather events (think: storms, floods, and heat waves) to increase both in frequency and intensity. In turn, this could lead to other indirect effects such as the spreading of tropical diseases to new regions, and forced mass migrations or climate refugees. The negative impacts will be strongest in low-income countries, as they are unable to take the necessary adaptation measures.