Wednesday 21 September 2016

The climate has changed before


The cool cartoonists at xkcd posted a world history of global temperatures that was graphically unimpeachable but flawed in the data it relied on. So great idea, and great graphics, but they produced another hockey stick.

Cartoonist Josh fixed it for them:


 CLICK FOR FULL-SIZE


I think I’d call this “context.”

[Hat tip Watts Up With That, where there’s a thriving debate down in the comments section.]
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1 comment:

Dinwar said...

It's actually worse for that xkcd graph than this indicates.

The problem is, we are currently in an ice age. Temperatures today are within normal range for interglacial periods in an ice age. While climate alarmists would have you believe that cool temperatures are normal, they're actually fairly wildly ABnormal--see Zachos et al., 2001, Figure 2 (while the details of that report are debated, that report is held to be a classic in climate change literature by the alarmists and the general trends are well-established). What that means is, to get back to what is actually normal for the planet we would need to raise the global temperature substantially.

Again, to be clear: Climate change alarmists want to perpetuate an ABNORMAL condition on the planet. Normal for Earth is hot compared to today.

We don't know what getting back to normal looks like. There is no ice age (in the larger sense) close enough in time to the modern era for modern paleoclimatological methods to be used. It could very well be that a sharp increase in temperature is how these events end. What we CAN know is that ice ages are far more volatile than normal periods in the Earth's climate history, so steep lines aren't a surprise to anyone.

This xkcd cartoon demonstrates why I generally refuse to discuss climate change with people. Climate change is INCREDIBLY complex stuff, requiring in-depth knowledge of a wide range of scientific disciplines, and if you don't have that depth of knowledge you're often fooled. Further, I've lost a lot of respect for xkcd. That graph committed one of the cardinal sins of graph making: manipulation of the start time for the graph to make their point look better. That's a mistake someone as intelligent as the author of xkcd should never have allowed himself to make. But since climate change is a political, not scientific issue (outside a handful of paleoclimatologists that's the truth of this debate), he obviously felt no need to address it rigorously.