Upper Air ReportAnnual 2001

Temperature Trends

During the past century, global surface temperatures have increased at a rate near 0.6°C/century (1.1°F/century), but this trend has dramatically increased to a rate approaching 2.0°C/century (3.6°F/century) during the past 25 years. There have been two sustained periods of warming, one beginning around 1910 and ending around 1945, and the most recent beginning about 1976. Temperatures during the latter period of warming have increased at a rate comparable to the rates of warming projected to occur during the next century with continued increases of anthropogenic greenhouse gases (IPCC, 2001).
Satellite measurements of tropospheric temperatures (the lowest 8 kilometers of the Earth's atmosphere) collected since 1979 also indicate warming, but not to the extent shown by surface observations. The adjacent figure shows annual anomalies for both the surface and tropospheric temperatures from 1979 to 2001. (Satellite measurements of lower tropospheric temperatures are collected by NOAA's TIROS-N polar-orbiting satellites via the Microwave Sounding Unit (MSU) and adjusted for time-dependent biases by NASA and the Global Hydrology and Climate Center at the University of Alabama in Huntsville). MSU/Surface Temperatures
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Global Stratospheric Temperatures
larger image		 While lower tropospheric temperatures as measured by the MSU indicate increasing temperature over the last 2 decades, stratospheric (14 to 22 km / 9 to 14 miles) temperatures have been decreasing. This is thought to be consistent with the depletion of ozone in the lower stratosphere. The large increase in 1982 was caused by the volcanic eruption of El Chichon, and the increase in 1991 was caused by the eruption of Mt. Pinatubo in the Philippines.

Citing This Report

NOAA National Centers for Environmental Information, Monthly Upper Air Report for Annual 2001, published online January 2002, retrieved on August 14, 2025 from https://www.ncei.noaa.gov/access/monitoring/monthly-report/upper-air/200113. DOI: https://www.ncei.noaa.gov/access/metadata/landing-page/bin/iso?id=gov.noaa.ncdc:C00762