According to Inter-Governmental Panel for Climate Change projections, we will see global average temperatures 2.6 to 4.8 degrees Celsius higher than the present by this century. Sea levels will also be 0.45 to 0.82 meters higher than today.
The likely range of total human-caused global surface temperature increase from 1850-1900 to 2010 to 2019 is 0.8 to 1.3 degrees Celsius. GHGs (greenhouse gases) contributed a 1 to 2 degrees Celsius rise. Aerosols and other human drivers caused a cooling of 0 degrees to 0.1 degrees Celsius.
Global average precipitation over land is also likely to have increased since 1950. Changes in near-surface ocean salinity have been observed. The upper ocean (0 to 700 m) has warmed, and oxygen levels have dropped since the 1970s. Sea levels rise averaged 1.3 mm between 1971 and 2006, increasing to 3.7 mm per year between 2006 and 2018. The land biosphere has been consistently warming, with climate zones shifting poleward in both hemispheres since the 1950s.
Some other climate-related facts noted in the 6th assessment report of IPCC are:
- CO2 concentrations were higher than at any time in at least two million years
- Concentrations of methane and nitrous oxide were higher than at any time in at least 800,000 years,
- The global surface temperature has increased faster since the 1970s
- Temperatures in the 2011-2020 decade exceeded the most recent multi-century warm period around 6500 years ago.
- Arctic sea ice has reached its lowest level since at least 1850. Global glaciers have retreated synchronously since the 1950s for at least 2000 years.
- Global mean sea levels have risen faster since 1900 and are warmed faster since the last deglacial transition around 11000 years ago.
- An increase in surface open ocean pH occurred over the past 50 million years, and surface open ocean pH has been as low as the last 2 million years in recent decades.
And I could go on and on. The weight in favor of climate change is huge.