What Natural Global Warming In The Past Tells Us About The Future

By Mathew Huber

Earth and Atmospheric Sciences Department and Climate Change Research Centre Purdue University

Lecture at Victoria University, 17 July 2009

Notes from Jonathan Kennett

  • There is very little uncertainty about climate change, other than the human element. How much oil, coal, etc will be removed from the earth and burnt?
  • A reasonable upper limit is 5000 GT and this would equate to 1000-1600 ppm of CO2e in the atmosphere.
  • Based on paleoclimate records and models this would result in an increase of 6-8 degrees by 2200, and the planet would stay that much warmer for several thousand years.
  • In the past the computer-based models have been too conservative and underestimated the sensitivity of climate to CO2. Projections published this year show greater warming that previously predicted.
  • Several parts of the IPCC 2007 report were wrong. Its scenarios did not have interactive ice sheets and did not project beyond 2100 because they said the scientific uncertainties increased with time. Huber said that the uncertainties do not increase with time and should be studied by IPCC.
  • Huber presented one graph that showed projections of only 1-2 degrees temperature rise in the future based. This was based on the possibility of massive emissions cuts now (80% or more). I presume this is why G8 leaders are talking about 80% emissions cuts by 2050.

Note: the 2007 IPCC report was what motivated Bronwen and Jonathan to purchase the Rameka property as a carbon sink.

Page last modified on 21 July 2009 at 02:08 PM