The Earth's Temperature History and How It Relates to Global Warming

This comes from the website for "The Great Global Warming Swindle" and can be seen here:
http://www.greatglobalwarmingswindle.co.uk/temperature_record.html

Peter


Temperature Record
One central problem for those who promote the idea of man made global warming is the earth’s temperature record – on almost all time scales.

In the last decade, there has been no clear warming trend (as the UK Met Office and IPCC’s own figures demonstrate). In the last century, much of the warming occurred prior to 1940, when human emissions of CO2 were relatively small compared to today. During the post-war economic boom (when one would have expected the temperature to rise) the world cooled, from the 1940s till the mid-70s (again, this is evident from accepted data used by the IPCC).

But it’s important to look back further in time 1,000 years. The climate record which used to be accepted as the standard account of this period was published in the first IPCC report. But this account posed a problem. A thousand years ago there was time a warm period – apparently warmer than today (known to climatologists as the Medieval Warm Period). This was followed by a relatively cold period (known as the Little Ice Age), from which, over the past two to three hundred years, seem to have made a slow, welcome recovery.

This has all rather undermined the idea that current temperatures were either unusual or alarming.

In subsequent IPCC reports the original graph was replaced by another – the famous ‘Hockey Stick’ (so-called because it looks like one). The Hockey Stick was a lot more dramatic, and was featured proudly on the top of the front page of the new IPCC reports. But was it true? The Hockey Stick debate is very telling, and we urge readers to review the links below.
Further back in time, still within our current ‘interglacial period, we find more warm spells – notably what geologists call the ‘Holocene Maximum’ when, for a few thousand years, the earth was significantly warmer than we find it today.

Over longer time periods of course, the earth has been far, far hotter than it is today (with tropical forests covering much of the earth) and also far, far colder, with much of the earth buried under miles of ice. The Earth’s climate has always changed, and changed without any help from us.

But there is another problem, a very major problem, for those who promote the idea of CO2-led global warming. According to global warming theory, if an enhanced greenhouse effect is responsible for warming the earth, then the rate of temperature rise should be greatest in that part of the earth’s atmosphere known as the troposphere, specifically in the tropics. And yet the observations, from weather balloons and satellites have consistently shown that not to be the case. I urge readers to look at the Christy et al papers below. The latest one was recently published in the Journal of Geophysical Research (2007).

More Information:
Arctic Temperatures – testimony by Syun-Ichi Akasofu, Director Int’l Arctic Research Centre read more

Harvard Gazette article – temperature over 1000 years read more

"An Economist’s Perspective on Climate Change and the Kyoto Protocol" By Ross McKitrick – with particular reference to Figure 3 read more

Hockey Stick debate explained read more

"What is the ‘Hockey Stick’ Debate About?" By Ross McKitrick*read more

Wegman report summary read more

Wegman Report in full read more

Getting rid of the medieval warm period read more

Witches and Weather
read more

Satellite and balloon temperatures See the work of John Christy and Roy Spencer, University of Alabama in Huntsville. Especially the Congressional Hearings which explain their work in simple termsread more

Earth Temperature History - Why The Panic Now?

The following is a graph showing temperture changes during the last 450,000 years. The data was derived from ice cores taken from the Antarctic Ice Sheet. The data is considered reliable because it correlates with temperature calculations from other sources, such as ocean and lake sediments, tree growth rings, and fossil evidence. What is immediately obvious is the Earth's climate is continually changing, in ways comparable to what we are seeing today. Long, long before we began burning fossil fuels.
Peter





Global temperature variation for the past 425,000 years. The present is at the right. The horizontal 0 line represents the 1961-1990 average global temperature. The numbers on the left show the variation from that baseline in °C.

The data were derived from an analysis of ice cores taken at the Vostok station in Antarctica. Find out more about how temperature estimates are made from proxy data.

Image based on data from the National Oceanographic and Atmospheric Administration.


The present day is at the far right of the chart. What do we see? First of all, there’s quite a bit of fluctuation. There are long periods of time when the average global temperature was as much as 9°C colder than now. These were Ice Ages. Much of the northern part of the world was covered with thick sheets of ice, much like we see today in Greenland and Antarctica. The most recent Ice Age ended about 12,000 years ago. There were also times when it was warmer than today. On the whole, we are in a relatively warm period. What causes these changes in climate? There are many factors. Find out more…