Dr Michael Mann on the IPCC report: We have ZERO years left to avoid climate change, it’s here

  • Published on August 9th, 2021

A short post on the just-published #IPCC #AR6 scientific working group (#WG1) report.

"Bottom line is that we have zero years left to avoid dangerous climate change, because it's here," @MichaelEMann IPCC report

By Dr Michael Mann

Three key takeaways:

1. The Hockey Stick grows longer, blade grows sharper. Recent warmth may be unprecedented in at least 100,000 years.

The Hockey Stick grows longer, blade grows sharper. Recent warmth may be unprecedented in at least 100,000 years.

2. Impacts of climate change are now “widespread and pervasive”. Climate change is NOW causing amplified weather extremes of the sort we’ve been witnessing this summer — droughts, heat waves, wildfires, floods, superstorms. The IPCC unambiguously connects the dots this time.

Impacts of climate change are now "widespread and pervasive". Climate change is NOW causing amplified weather extremes of the sort we’ve been witnessing this summer — droughts, heat waves, wildfires, floods, superstorms. The IPCC unambiguously connects the dots this time.

3. Urgency AND agency: We can prevent the worst impacts (e.g. multiple meters of sea level rise) through bold action in the years ahead. The crucial message going into #COP26.

3. Urgency AND agency: We can prevent the worst impacts (e.g. multiple meters of sea level rise) through bold action in the years ahead. The crucial message going into #COP26 https://t.co/mHH42u7KGaBottom line is that we have zero years left to avoid dangerous climate change, because it’s here.

Ignore the climate-denying and climate action-delaying trolls & trollbots today. They’re going to try to deflect attention from the urgent new #IPCC report. Provide them no oxygen. Block and report if you must but don’t engage.

 

A Tale of Two Hockey Sticks

(Posted at RealClimate)

Two decades ago, the so-called “Hockey Stick” curve, published in 1999 by me and my co-authors (Mann, Bradley and Hughes, 1999), was featured in the all-important “Summary for Policy Makers” (SPM) of the 2001 IPCC Third Assessment report. The curve, which depicted temperature variations over the past 1000 years estimated from “proxy data such as tree rings, corals, ice cores, and lake sediments”, showed the upward spiking of modern temperatures (the “blade”) as it dramatically ascends, during the industrial era, upward from the “handle” that describes the modest, slightly downward steady trend that preceded it.

The Hockey Stick became an icon in the case for human-caused climate change, and I found myself at the center of the contentious climate debate (I’ve described my experiences in “The Hockey Stick and the Climate Wars”).

Featured two decades later now in the AR6 SPM is a longer Hockey Stick with an even sharper blade. And no longer just for the Northern Hemisphere, it now covers the whole globe. The recent warming is seen not only to be unprecedented over the past millennium, but tentatively, the past hundred millennia.

Side-by-side comparison of the (left) original Mann et al (1999) “Hockey Stick” reconstruction as featured in the Summary for Policy Makers of the IPCC 3rd Assessment report (2001) and the (right) longer, sharper “Hockey Stick” as featured in the Summary for Policy Makers of the IPCC 6th Assessment report (2021).
Side-by-side comparison of the (left) original Mann et al (1999) “Hockey Stick” reconstruction as featured in the Summary for Policy Makers of the IPCC 3rd Assessment report (2001) and the (right) longer, sharper “Hockey Stick” as featured in the Summary for Policy Makers of the IPCC 6th Assessment report (2021).

(Read the rest at RealClimate)




About the Author

Dr. Michael E. Mann is Distinguished Professor of Atmospheric Science at Penn State, with joint appointments in the Department of Geosciences and the Earth and Environmental Systems Institute (EESI). He is also director of the Penn State Earth System Science Center (ESSC). Dr. Mann was a Lead Author on the Observed Climate Variability and Change chapter of the Intergovernmental Panel on Climate Change (IPCC) Third Scientific Assessment Report in 2001 and was organizing committee chair for the National Academy of Sciences Frontiers of Science in 2003. He has received a number of honors and awards including NOAA's outstanding publication award in 2002 and selection by Scientific American as one of the fifty leading visionaries in science and technology in 2002.

What do you think? We'd love to hear your thoughts...

This site uses Akismet to reduce spam. Learn how your comment data is processed.