The global average surface temperature has risen significantly since the pre-industrial era (1850-1900), increasing by roughly 2 degrees Fahrenheit (1 degree Celsius). This seemingly small change represents a massive increase in accumulated heat, impacting global systems. This extra heat is driving regional and seasonal temperature extremes, reducing snow cover and sea ice, intensifying heavy rainfall, and altering habitats for plants and animals.
Land areas are warming faster than oceans, and the Arctic is experiencing the most rapid warming. The rate of warming in recent decades is significantly faster than the 20th-century average.
Calculating a global average temperature involves compiling temperature measurements from locations worldwide and converting them into temperature anomalies – the difference between the observed temperature and the long-term average for that location and date. This data allows scientists to monitor changes in Earth’s energy budget – the balance between absorbed sunlight and radiated heat.
Every month in 2023 ranked among the seven warmest for its respective month, with June through December each being the hottest on record. July, August, and September marked the first time any month exceeded 1.0°C (1.8°F) above the long-term average.
2023 was the warmest year on record for both land and ocean areas individually and combined. It was also the warmest year for both the Northern and Southern Hemispheres, marking the 40th warmest year for Antarctica and the 4th warmest for the Arctic.
The combined land and ocean temperature has increased at an average rate of 0.11°F (0.06°C) per decade since 1850. However, the warming rate since 1982 has more than tripled to 0.36°F (0.20°C) per decade. The scientific consensus, as stated by the Intergovernmental Panel on Climate Change (IPCC), attributes this warming trend unequivocally to human activities, primarily greenhouse gas emissions.
Human activities, mainly fossil fuel combustion and deforestation, release about 11 billion metric tons of carbon into the atmosphere annually, exceeding the capacity of natural processes to remove it. This continuous increase in atmospheric carbon dioxide levels leads to a continuous rise in global temperatures.
Projected future warming depends on future greenhouse gas emissions. If emissions continue to rise rapidly, global temperatures could increase by at least 5 degrees Fahrenheit by the end of the century, potentially reaching a 10.2-degree increase. Even with slower emission growth and significant declines by 2050, temperatures are projected to rise by at least 2.4 degrees. These findings underscore the urgent need for global action to address climate change and mitigate its impacts.