Average surface temperature of earth
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Global Average Surface Temperature: Key Estimates and Trends
The average surface temperature of Earth is a fundamental metric for understanding climate and environmental changes. Multiple studies have provided estimates and examined the factors influencing this value.
Current Estimates of Earth's Average Surface Temperature
The most widely cited estimate for the annual average surface temperature of the world is 14.0°C, with the Northern Hemisphere averaging 14.6°C and the Southern Hemisphere 13.4°C. This estimate is based on comprehensive climatology data, primarily from 1961–1990, and is considered highly reliable due to extensive data interpolation and validation efforts . Satellite data from 2003–2019 corroborate these findings, showing strong agreement with global annual air temperatures reported by major climate centers .
Historical and Long-Term Variability
Over the past 485 million years, Earth's global mean surface temperature (GMST) has varied widely, ranging from 11°C to 36°C. This long-term record highlights that Earth has spent more time in warmer climates than in colder ones, with atmospheric carbon dioxide (CO2) identified as the dominant control on these temperature variations .
Recent Temperature Changes and Warming Trends
Analyses of temperature records from 1880 to the present show a clear warming trend. Since 1880, the global average surface temperature has increased by about 0.08°C per decade, with the rate of warming more than doubling since 1981 to 0.18°C per decade . From the 1950s to the 2000s, the land surface temperature rose by approximately 0.90°C . Satellite and ground-based measurements confirm a consistent upward trend, with a recent increase of about 0.021°C per year from 2003 to 2019 .
Measurement Accuracy and Uncertainty
Studies comparing different temperature series and methodologies find that the absolute monthly and globally averaged temperature is accurate within about ±0.1°C, and the change since 1880 is estimated correctly within ±0.1°C . This high level of agreement across independent datasets and methods increases confidence in the reported global average temperature.
The Role of Solar and Internal Earth Heating
Mathematical models show that solar heating alone would result in a much colder Earth, with an average surface temperature around -50°C. This suggests that additional sources, such as internal heat from the Earth itself, play a role in maintaining the observed surface temperature 14.
Conclusion
The best current estimate for the average surface temperature of Earth is about 14.0°C, supported by both ground-based and satellite data. This value has increased significantly over the past century due to rising greenhouse gas concentrations, especially CO2. While Earth's temperature has fluctuated greatly over geological timescales, recent trends show a clear and measurable warming, with high confidence in the accuracy of these measurements.
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