Published today in Science, the paper A Reconstruction of Regional and Global Temperature for the Past 11,300 Years (Marcott et.al) shows the stunning – hell, terrifying – increase in temperatures that has taken place since industrialisation.
Michael Mann’s famous hockey stick graph reconstructed the temperature for the last 2000 years. It not only became iconic, but a target for those wishing to cast doubt on the science.
Marcott et.al. do not merely replicate Mann’s work, but extend the time-frame to cover the previous 11,000 years:
Surface temperature reconstructions of the past 1500 years suggest that recent warming is unprecedented in that time. Here we provide a broader perspective by reconstructing regional and global temperature anomalies for the past 11,300 years from 73 globally distributed records. Early Holocene (10,000 to 5000 years ago) warmth is followed by ~0.7°C cooling through the middle to late Holocene (<5000 years ago), culminating in the coolest temperatures of the Holocene during the Little Ice Age, about 200 years ago. This cooling is largely associated with ~2°C change in the North Atlantic. Current global temperatures of the past decade have not yet exceeded peak interglacial values but are warmer than during ~75% of the Holocene temperature history. Intergovernmental Panel on Climate Change model projections for 2100 exceed the full distribution of Holocene temperature under all plausible greenhouse gas emission scenarios.
To put into perspective, before the founding of the first cities.
Our civilisation has existed in “the sweetest of sweet spots” – a time of relatively stable climatic conditions.
In the last 10,000 years we have seen the emergence of agriculture, the establishment of great cities, the founding of great civilisations and the invention of writing.
None of this would have been possible without a benign and forgiving climate.
What is different about the past century and a half is the speed of those changes: note the spike in temperature anomalies for what is essentially the period of industrialisation (1850 ff).
The climate has always changed: no self-respecting scientist or climatologist has ever denied this. Temperature records are but one proxy of this change – the multiple lines of evidence for climate change are overwhelming.
Note also the last sentence in that abstract: Intergovernmental Panel on Climate Change model projections for 2100 exceed the full distribution of Holocene temperature under all plausible greenhouse gas emission scenarios.
To translate: all the models point to a future that is warmer than anything we’ve seen for the last 10,000 years.