The Hockey Stick, 20 years on

Hat tip to Climate Denial Crock of the Week.

From the AGU100 Blogosphere:

When we look back on 20th-century science a few decades from now, a few images that stand out above the rest. Earthrise may be the most famous. It was taken by Apollo 8 Astronaut Bill Anders 50 years ago last December. I’ve written before about how that single image changed the way we humans see our planet. 

Here’s another image that also led to a dramatic change in how we see our planet:

That graph that would become known as the hockey stick. It was published in a paper by Dr. Michael Mann et. al on 15 March 1999 in the AGU Journal Geophysical Research Letters.

The stick was a powerful image showing how fast our planet’s temperature was rising compared to the stable climate of the past 1000 years. In 1999, there were a large number of people who insisted that the planet was not warming at all, and some even insisted that a new ice age was looming! The hockey stick showed clearly that we were indeed warming, and that something bad was happening to our stable climate. 

Twenty years have passed, and the hockey stick has stood up against the firestorm of criticism it elicited.  (Read this.) Most of that was from people with no background in science. Those who talk about any science quickly learn that when you show someone information that conflicts with their worldview, they will often dismiss it and or get angry, and accuse you of showing them fake data. This includes people who do not believe in vaccines and others who DO believe in chemtrails, UFO’s, or that pro-wrestling is real.

Source: Stefan Rahmstorf

All of this happened to Dr. Mann after that paper was published, and all of it fell by the wayside as others did what science requires: replication.

If others cannot replicate your work, it will not be accepted as good science.

Other scientists did indeed replicate it, and improved upon it, with newly recovered data and observations. Dr. Mann improved his first graph with even better data as well. This week, a more recent version was posted on Twitter this week by Climatologist Stefan Rahmstorf. The stick is even sharper now and gets more so every year. It now shows how unusual the last 100 years have been.

In his book, Brian Fagan (the renowned archeologist) has called the stable climate of the Holocene, “The Long Summer“.  All of human civilization developed in the stable climate of the last 6,000 years, but the data clearly shows that a real heat wave is headed for humanity and we are running out of time to deal with it.

[Read more here]

We need to start cutting emissions.  As fast as, and as soon as, we can. If we could cut emissions by a compound 5% a year we could reduce them by 80% by 2050.   That has to be our target.  And we could start by never building another coal-fired power station anywhere in the world ever again, while steadily closing down the old coal power stations which are wearing out.