History of climate change since 1850
Climate change is already having an impact today, and the warming is mainly due to human emissions of greenhouse gases.
The effects of climate change are already discernible
The mean global temperature has increased by approximately 1.1°C since industrialisation began, with greater warming seen over land (+1.6°C) than over the oceans (+0.9°C). This rate of warming is unprecedented in the last 2,000 years. The consequences have now become evident and verifiable in every corner of the globe. Other impacts of climate change include rising sea levels, melting ice masses, thawing permafrost, and shrinking snow cover. Many of the climate and weather extremes that have occurred in recent years are partly the result of climate change. There has been a measurable increase in hot-temperature extremes in almost every region of the Earth, and many regions have also seen increases in precipitation extremes or drought.
Human influence on climate change has been proven beyond doubt
It has been unequivocally proven that humans are the primary contributors to global warming. According to the IPCC, almost every observed instance of warming can be attributed to human activity. Purely natural factors (such as solar activity, volcanic eruptions or changes in the Earth’s orbit) are not sufficient to explain the increase in the mean global temperature, which is clearly and causally related to increasing concentrations of greenhouse gases in the atmosphere, and, in particular, of carbon dioxide concentrations due to human use of fossil fuels.
The CO2 concentration measured in the atmosphere is currently the highest it has been for at least two million years. In addition to CO2, other greenhouse gases that contribute to climate change include methane (CH4) and nitrous oxide (N2O). The warming caused by greenhouse gases is only partially mitigated by the cooling effect of aerosols.