Satellite data shows globe will stay below 1.5°C target at the current rate of warming, resulting in 1.1°C
The average temperature of Earth’s atmosphere has warmed just over four tenths of a degree Celsius (almost three fourths of a degree Fahrenheit) during the past 37 years, with the greatest warming over the Arctic Ocean and Australia, said Dr. John Christy, director of the Earth System Science Center at The University of Alabama in Huntsville. Microwave sounding units on board NOAA and NASA satellites completed 37 complete years of collecting temperature data in November, giving us nearly global coverage of climate change during that time.
If that trend was to continue for another 63 years, the composite warming for the globe would be 1.1 C (about 2 degrees Fahrenheit) for the century, Christy said. That would put the average global temperature change over 100 years well under the 2.0 C (3.6 degrees F) goal set recently at the climate change summit in Paris.
Due in part (but not exclusively) to the ongoing El Niño Pacific Ocean warming event, the global temperature trend has been trending slightly warmer over the past several months, Christy said. While the current global trend is just under 0.115 C (rounded down to 0.11), he expects the trend line to cross 0.115 C in the next several months, raising the global trend to 0.12 C per decade.
Two major volcanic eruptions in the first half of the 37-year satellite temperature record (El Chichon in 1982 and Mount Pinatubo in 1991) depressed temperatures over large portions of the globe. While natural events, their random eruptions during the first half of the dataset has the effect of tilting the trend upward more than it otherwise would have been.
While a 0.12 C trend isn’t exactly a sprint to climate catastrophe (the 1.2 C or 2.2 degrees F rise over 100 years would be roughly equal to the warming seen most spring days between 10 a.m. and noon), it nonetheless has been a steady trend for the past several years. Take away the random variations caused by warm and cold weather systems, and any long-term trend, no matter how small, will produce climate records on a regular basis. Add to that long-term warming the additional heat of a large El Niño, and record-setting monthly average temperatures should be both routine and expected.
Despite that, early indications are that 2015 will end as the third warmest year in the satellite temperature record, behind 1998 and 2010. That is the early indication. Typically, the warmest temperatures are seen in the second year of an El Niño warming event, although there have been exceptions. If the typical pattern holds true, the second year of the current El Niño would be expected to bring more record high temperatures in 2016, perhaps including a new record high temperature for the year.
The fastest warming place on Earth over the past 37 years has been in the Arctic Ocean north of the Svalbard archipelago, where temperatures have been rising 0.5 C (about 0.9 degrees F) per decade. The fastest cooling spot was over the eastern Antarctic near Dome C. Temperatures there have been falling at the rate of 0.41 C (about 0.74 degrees F) per decade.
Global Temperature Report: 12/1978 through 11/2015
Global climate trend since Nov. 16, 1978: +0.11 C per decade
37-year temperature trends:
Global average trend.: +0.11 C (about 0.20 degrees Fahrenheit) per decade since December 1978.
Northern Hemisphere: +0.14 C (about 0.25 degrees Fahrenheit) per decade since December 1978.
Southern Hemisphere: +0.09 C (about 0.16 degrees Fahrenheit) per decade since December 1978.
Tropics: +0.10 C (about 0.18 degrees Fahrenheit) per decade since December 1978.
37-year composite changes:
Global Composite: +0.41 C (about 0.73 degrees Fahrenheit) composite change since December 1978.
Northern Hemisphere: +0.52 C (about 0.93 degrees Fahrenheit) composite change since December 1978.
Southern Hemisphere: +0.33 C (about 0.60 degrees Fahrenheit) composite change since December 1978.
Tropics: +0.37 C (about 0.67 degrees Fahrenheit) composite change since December 1978.
Trend per decade Composite
Globe +0.11 C +0.41 C
Land +0.20 C +0.74 C
Ocean +0.08 C +0.30 C
N.H. +0.14 C +0.52 C
Land +0.21 C +0.78 C
Ocean +0.09 C +0.33 C
S.H. +0.09 C +0.33 C
Land +0.18 C +0.67 C
Ocean +0.07 C +0.26 C
Tropics +0.10 C +0.37 C
Land +0.21 C +0.38 C
Ocean +0.07 C +0.26 C
NoPole +0.23 C +0.85 C
Land +0.19 C +0.70 C
Ocean +0.26 C +0.96 C
SoPole -0.01 C -0.04 C
Land -0.01 C -0.04 C
Ocean -0.01 C -0.04 C
USA48 +0.19 C +0.70 C
Australia +0.24 C +0.89 C
The complete version 6 beta lower troposphere dataset is available here:
Archived color maps of local temperature anomalies are available on-line at:
As part of an ongoing joint project between UAHuntsville, NOAA and NASA, Christy and Dr. Roy Spencer, an ESSC principal scientist, use data gathered by advanced microwave sounding units on NOAA and NASA satellites to get accurate temperature readings for almost all regions of the Earth. This includes remote desert, ocean and rain forest areas where reliable climate data are not otherwise available.
The satellite-based instruments measure the temperature of the atmosphere from the surface up to an altitude of about eight kilometers above sea level. Once the monthly temperature data are collected and processed, they are placed in a “public” computer file for immediate access by atmospheric scientists in the U.S. and abroad.
Neither Christy nor Spencer receives any research support or funding from oil, coal or industrial companies or organizations, or from any private or special interest groups. All of their climate research funding comes from federal and state grants or contracts.
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