I wrote about Andrew Gilkson and his public lecture on climate change some time ago. I heard him again in a presentation and discussion for a small group in recent days. Those present were informed and intelligent and interested and ultimately disheartened by the state of our climate. This was a presentation of the science. Plenty of charts of observations. Plenty of peer-reviewed knowledge. Just a touch of leering at the deniers, not just of climate change, but rationality and scientific method and Enlightenment values. And a touch of philosophical thinking, on living in the present, satisfying one's conscience, doing what's right even if a good outcome seems unlikely. The news is not good. Some things I learnt: CO2 remains in the atmosphere for thousands of years; methane may be a more potent greenhouse gas, but it degrades within 100 years to CO2; the anthropogenic greenhouse gas forcing is now ~2.3degC but it's balanced by ~-1.2degC of aerosols, dust and similar in the atmosphere to give our net ~1.1degC temperature rise (usually quoted as +0.9degC); aerosols, dust etc (eg, from burning coal) drops out of the atmosphere within a month (essentially inadvertent geo-engineering); natural catastrophic events have doubled since 1980 (from Munich Re-Insurance, no less). There was more on interstitial cycles, glacial termination tipping points, polar ice melt and sea level rise, thermohaline circulation, shorter and longer term changes. Suffice to say, I looked up at one point to see some dejected faces, not from a poor session but from clearer realisations. All our time on earth as a civilised species has been spent within a small range of average temperature (~-0.8-+0.5degC); we are now entering temperatures that have never been experienced in the 10,000 years of human civilisation. We are changing all this and it's happening at breakneck speed (in geological and evolutionary terms).
I like civilisation; I want to be able to go to jazz clubs in Manhattan (remember, Manhattan has already flooded and it cost $US60b to repair); I don't want to live in a cave. Contrary to the flippant line, it's the climate change deniers that will have us living in caves as we abandon Manhattan and modern life as it becomes uneconomic to support. It's happened before; civilisations have disappeared due to changed weather (eg, the Fertile crescent of ancient Mesopotamia is dry). Queensland floods cost $6b a few years back but we rebuilt in the same place. I republish a graph that was only poorly presented in my last write-up of Andrew Glikson. James Lovelock (Gaia Hypothesis) suggested humans will end as a few hundred mating pairs at the poles; apparently Carl Sagan suggested (in the context of nuclear weapons) that technological societies may only survive a few hundred years after discovery of the atom; Limits to Growth, despite its own denialist protestations, is tracking well*.
"We’ll undergo the same fate as the people on Easter Island. Climate change is just at the very beginning. But we’re seeing remarkable changes in the weather already…. The human species is likely to go the same way as many of the species that we’ve seen disappear. Homo sapiens will become extinct, perhaps within 100 years" / Frank Fenner on climate change, to The Australian, 16 June 2012