The fact that human activity adds carbon dioxide to the Earth’s climate system is undeniable.
Meteorological measurements slightly before, during and after the twentieth century show a mean surface temperature increase of around 0.6°C.
Thsee two paragraphs are strongly linked. Here’s how.
The recent increased amount of greenhouse gasses in the atmosphere can be traced back to fossil fuel burning and deforestation through isotopic composition and other signatures.
As documented in tree rings, corals, ice cores and other climatic indicators – 1000 years before the 20th century, there was an irregular, but constant cooling of around 0.2°C, and the mean fluctuations from century to century were less than 0.3°C.
Mathematical models taking into account global temperatures tied in with atmospheric greenhouse gas levels have predicted and correctly confirmed changes in the climate both today and before, therefore, we can assume they are accurate when extrapolated to the direction in question, showing the human “fingerprints” of the enhanced greenhouse effect.
“Dangerous interference with the climate system”, as described by the UN IPCC (Intergovernmental Panel on Climate Change), can arise if the temperature rises to a certain point – a tipping point. If emissions continue as they are today, this value is put between 1.5 to 4.5°C by the IPCC, and most researchers have suggested values within that range. Simulations predict that the lower limit increase of 1.5°C could be reached in 20-30 years.
The message is clear.