Monday, 20 April 2015

The Warming Earth - Temperature evidence, and the "2 degree limit"

Claiming "global temperatures have not risen for ..... years " is a popular quote.
But actually the temperature has risen.

This chart shows the annual average global temperatures from NASA's Goddard Institute for Space Studies (GISS)

One thing to note ….. every La Nina ‘year’ since 1998 was warmer than every El Nino ‘year’ before 1995.  

It's useful to look at average global temperatures by comparing decades.
This chart comes from the World Meteorological Organisation.

The high figures in the 1930s and 1940s were produced because there were strong El Ninos over a period from about 1939 to 1942.

Since the mid 20th century global temperatures have risen, decade by decade.

New research published June 2015 confirms this trend:

Over a longer term, it's obvious that the current situation is unusual.

A temperature rise of 2 degrees C above pre-industrial temperature has been agreed as a threshold beyond which climate change risks become unacceptably high.

However, there are a few major objections to the "two-degree limit".
Many say the number is simply too high.

Archbishop Desmond Tutu has pointed out that a two-degree global average rise might result in Africa’s temperature rising as much as 3.5 degrees—a potentially disastrous change.

The current rise has reversed the natural trends.

The graph uses data from modern temperature records, plus information about the past from a research paper that combined data from over 70 different scientific studies.

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