Many climate change impacts are already felt at the current 1.2 °C (2.2 °F) level of warming. Additional warming will increase these impacts and can trigger tipping points, such as the melting of the Greenland ice sheet. Under the 2015 Paris Agreement, nations collectively agreed to keep warming "well under 2 °C". However, with pledges made under the Agreement, global warming would still reach about 2.7 °C (4.9 °F) by the end of the century. Limiting warming to 1.5 °C will require halving emissions by 2030 and achieving net-zero emissions by 2050.
The campaign to undermine public trust in climate science has been described as a "denial machine" organized by industrial, political and ideological interests, and supported by conservative media and skeptical bloggers to manufacture uncertainty about global warming.
The following are images from various climate-related articles on Wikipedia.
Image 1Mean temperature anomalies during the period 1965 to 1975 with respect to the average temperatures from 1937 to 1946. This dataset was not available at the time. (from History of climate change science)
Image 2The rising accumulation of energy in the oceanic, land, ice, and atmospheric components of Earth's climate system since 1960. (from Earth's energy budget)
Image 3Global average temperatures show that the Medieval Warm Period was not a planet-wide phenomenon, and that the Little Ice Age was not a distinct planet-wide time period but rather the end of a long temperature decline that preceded recent global warming. (from Temperature record of the last 2,000 years)
Image 9Earth's climate is largely determined by the planet's energy budget, i.e., the balance of incoming and outgoing radiation. It is measured by satellites and shown in W/m2. The imbalance (or rate of global heating; shown in figure as the "net absorbed" amount) grew from +0.6 W/m2 (2009 est.) to above +1.0 W/m2 in 2019. (from Earth's energy budget)
Image 10Observed temperature from NASA vs the 1850–1900 average used by the IPCC as a pre-industrial baseline. The primary driver for increased global temperatures in the industrial era is human activity, with natural forces adding variability. (from Attribution of recent climate change)
Image 11CO2 sources and sinks since 1880. While there is little debate that excess carbon dioxide in the industrial era has mostly come from burning fossil fuels, the future strength of land and ocean carbon sinks is an area of study. (from Attribution of recent climate change)
Image 12The growth in Earth's energy imbalance from satellite and in situ measurements (2005–2019). A rate of +1.0 W/m2 summed over the planet's surface equates to a continuous heat uptake of about 500 terawatts (~0.3% of the incident solar radiation). (from Earth's energy budget)
Image 15Annual CO2 flows from anthropogenic sources (left) into Earth's atmosphere, land, and ocean sinks (right) since year 1960. Units in equivalent gigatonnes carbon per year. (from Carbon dioxide in Earth's atmosphere)
Image 16The greenhouse effect traps infrared heat, and ultimately raises Earth's surface temperatures. (from Earth's energy budget)
Image 19Since the 1980s, global average surface temperatures during a given decade have almost always been higher than the average temperature in the preceding decade. (from History of climate change science)
Image 25Modeled simulation of the effect of various factors (including GHGs, Solar irradiance) singly and in combination, showing in particular that solar activity produces a small and nearly uniform warming, unlike what is observed. (from Attribution of recent climate change)
Image 28Atmospheric CO2 concentrations measured at Mauna Loa Observatory from 1958 to 2022 (also called the Keeling Curve). Carbon dioxide concentrations have varied widely over the Earth's 4.54 billion year history. However, in 2013 the daily mean concentration of CO2 in the atmosphere surpassed 400 parts per million (ppmv) - this level has never been reached since the mid-Pliocene, 2 to 4 million years ago. (from Carbon dioxide in Earth's atmosphere)
Image 39Frequency of occurrence (vertical axis) of local June–July–August temperature anomalies (relative to 1951–1980 mean) for Northern Hemisphere land in units of local standard deviation (horizontal axis). According to Hansen et al. (2012), the distribution of anomalies has shifted to the right as a consequence of global warming, meaning that unusually hot summers have become more common. This is analogous to the rolling of a dice: cool summers now cover only half of one side of a six-sided die, white covers one side, red covers four sides, and an extremely hot (red-brown) anomaly covers half of one side. (from Attribution of recent climate change)
Image 41This diagram of the fast carbon cycle shows the movement of carbon between land, atmosphere, and oceans in billions of metric tons of carbon per year. Yellow numbers are natural fluxes, red are human contributions, white are stored carbon. (from Carbon dioxide in Earth's atmosphere)
Image 42Greenhouse gases allow sunlight to pass through the atmosphere, heating the planet, but then absorb and re-radiate the infrared radiation (heat) the planet emits (from Carbon dioxide in Earth's atmosphere)
Sea level trends between 1993 and 2010. Per the U.S. National Oceanic and Atmospheric Administration (NOAA), "The following maps provide estimates of sea level rise based on measurements from satellite radar altimeters. The local trends were estimated using data from TOPEX/Poseidon (T/P), Jason-1, and Jason-2, which have monitored the same ground track since 1992.
An inverted barometer has been applied. The estimates of sea level rise do not include glacial isostatic adjustment effects on the geoid, which are modeled to be +0.2 to +0.5 mm/year when globally averaged."