Earth historical temperature changes
Pro Research Analysisby 
Searched over 200M research papers
Long-Term Earth Historical Temperature Changes: Phanerozoic to Present
Global Mean Surface Temperature Over Hundreds of Millions of Years
Earth’s global mean surface temperature (GMST) has changed dramatically over the past 485 million years, ranging from about 11°C to 36°C. Most of this time, the planet was warmer than today, with distinct climate states such as icehouse (cold) and greenhouse (warm) periods. The main driver of these long-term temperature changes has been atmospheric carbon dioxide (CO2), which shows a strong correlation with GMST. The sensitivity of Earth’s climate to CO2 over these timescales is estimated to be about 8°C for a doubling of CO2, much higher than current short-term estimates. This suggests that CO2 has been the dominant force shaping Earth’s climate history, even as other factors like solar luminosity and planetary albedo played compensating roles Judd2024Snyder2016.
Temperature Trends Over the Last Two Million Years
Over the past two million years, Earth’s temperature gradually cooled until about 1.2 million years ago, after which the cooling trend stalled. This cooling set the stage for the shift to longer glacial cycles. During the last 800,000 years, temperature changes at the poles have been amplified compared to the global average, and temperature and greenhouse gas concentrations have remained closely linked. The long-term sensitivity of the climate system to CO2 over these timescales is estimated at 7–13°C per doubling, indicating that current greenhouse gas levels may commit Earth to significant future warming as slow feedbacks play out .
Surface Temperature Since the Last Glacial Maximum
In the last 24,000 years, since the Last Glacial Maximum, global mean temperature has increased by about 0.5°C since the early Holocene (about 9,000 years ago). This warming has been driven by a combination of radiative forcing from greenhouse gases and changes in ice sheets, as well as shifts in ocean circulation and seasonal sunlight. The rate and magnitude of modern warming are unusual compared to the relatively steady changes of the past 24,000 years .
Temperature Changes in the Last Millennium
During the last 1,000 years, natural variability has caused significant temperature swings, including the Medieval Warm Period (900–1400 AD) and the Little Ice Age (1400–1800 AD). About half of the warming observed since 1850 may be attributed to natural millennial-scale oscillations, with the rest due to human activities. The equilibrium climate sensitivity to CO2 over this period is estimated to be lower (1.0–2.3°C per doubling), suggesting that both natural and anthropogenic factors have played roles in recent temperature changes .
Global Temperature Changes Since the Preindustrial Era
The preindustrial period, best defined as 1720–1800, was about 0.55–0.80°C cooler than the late 20th century (1986–2005). By 2015, global average temperature had risen more than 1°C above preindustrial levels. This warming is primarily due to increased greenhouse gas concentrations from human activities .
Surface Air Temperature Over the Past 150 Years
Over the last 150 years, global surface air temperature has increased by about 0.6°C, with the most significant warming occurring in two periods: 1925–1944 and 1978–1997. The annual average surface temperature of the world is currently about 14.0°C. In recent decades, nighttime minimum temperatures have increased more than daytime maximums, leading to a reduced diurnal temperature range .
Recent and Modern Temperature Records
Since 1980, new high temperature records have been set across much of the world, with the 2010–2020 decade being the warmest on record for over a third of the Earth’s surface. About 60% of the land surface recorded new maximum annual mean temperatures after 2010, and 2020 was the warmest year recorded in many regions . Since 1880, the rate of warming has accelerated, with the most rapid increases occurring since 1981 .
Causes of 20th Century Temperature Change
The warming observed since 1900 is largely attributed to human-caused increases in greenhouse gases and aerosols, especially since 1946. Earlier warming in the century may have involved a mix of natural and anthropogenic factors, but recent decades are dominated by human influence .
Uncertainty in Historical Temperature Records
Recent advances have improved the characterization of uncertainty in global temperature records, allowing for more reliable assessments of temperature trends at global, regional, and monthly scales. These improvements provide greater confidence in the observed patterns of historical temperature change .
Conclusion
Earth’s temperature history reveals a dynamic climate system, with large swings over millions of years driven mainly by CO2 and other greenhouse gases. In the last two centuries, human activities have become the dominant force behind rapid warming, setting new temperature records and altering the climate at a pace and magnitude unusual in the context of the past 24,000 years. Understanding these changes provides essential context for current and future climate challenges.
Sources and full results
Most relevant research papers on this topic