One of the most contested graphs in climate science has been the hockey stick. Inconveniently for gain-sayers later science has confirmed the shape of the thing as sites such as Skeptical Science and New Scientist confirm.
The hockey stick was confined to temperatures for the last 1000 years. Graphs of the whole Holocene era were rare, although they did exist, as the featured image above. Now a study by Marcott et al has used 73 proxies to study average global temperature for the whole Holocene period of the last 11,300 years. You can read about it at New Scientist, Mother Jones, Climate Progress here and here.
Here’s a version of the graph from the Mother Jones post, graduated in Fahrenheit:
I’ve chosen it because it shows the shape very clearly and identifies the last 100 years.
The New Scientist graph shows the current temperature as roughly the same or a little below the Holocene maximum. Michael Mann reckons the study has a bias towards the poles, which would mean that historical temperatures were possibly a bit lower than shown. It really doesn’t matter. When you take the longer geological perspective something is turbo charging the thing. It’s taking off like a rocket. Any wrinkles or claimed ‘pauses’ for a decade or three won’t even show.
Now look where it’s headed from this graph via Climate Progress:
Effectively we are in the process of blowing up in a geological instant the climate system in which our civilisation developed.
Meanwhile in 2012 atmospheric carbon levels increased by 2.67 ppm, the second largest annual rise since 1960.
Closer to home our Climate Commission has recently released its The Angry Summer report. We are told that:
The Australian summer over 2012 and 2013 has been defined by extreme weather events across much of the continent, including record-breaking heat, severe bushfires, extreme rainfall and damaging flooding. Extreme heatwaves and catastrophic bushfire conditions during the Angry Summer were made worse by climate change.
It’s particularly difficult to predict the effects of climate change on a regional basis. The smaller the region the greater the uncertainty. Nevertheless it seems we are on the threshold of leaving the Holocene and entering the Anthropocene. Aiming at a guardrail of a 2C increase in temperatures is not a recipe for a safe climate.
Update: Here’s the graph constructed by Tamino at Open Mind showing the temperature from 20,000 years BC: