Over at Peter Sinclair’s Climate Crock’s, Peter and many of his commentators provide other readers with well written, informative answers to questions raised in the comment sections. For my mind, this is one that not only falls into the category I mentioned but does so in such an easy to read blunt but courteous manner it makes for compelling reading. If more people could explain things as simply as this gentleman does, many others would be better informed.
tweetingdonal Says:Calving like this is not “ONLY” explained by global warming. There are lots of conditions that have to be met for something like this to happen. If we look at the last 4.5 billion years, this has undoubtedly happened before. In fact it’s likely happened in the past 50 million years quite a few times.
While we can’t prove it definitively, events like the extreme calving seem to have been rare since modern humans emerged. Has the human race seen circumstances like this before? Something similar might have happened, but not often.
The Climate System is still catching up. We’ve forced more heat and more contaminants onto our planet faster than has EVER happened since humans have existed. One way to look at how fast we’re changing things is to compare the average temperature change leading up to one of the global extinctions. The average temperature change leading up to the most recent global extinction was between 4 to 7 degrees over the course of 5,000 years. Since 1900 our average temperature change has been around 0.7 degrees.
It might sound like a small rise in temperature, but the rates of temperature change are more telling. Doing the arithmetic, the average temperature change per decade around extinction events was about 0.008 degrees per decade. Since 1900 we’ve been averaging a 0.06 degree per decade change. (Per the European Environment Agency). So that 0.7 degree change is over 7 times as fast as the events leading up to the last great extinction even.
Our rate of change in the last decade has grown from 0.06 to 0.20 degrees, making the rate of change about 25 times the last global extinction event. As a cross check to that number, our current rate of species extinction is actually around 45 times the normal “background” rate.
Thinking about it this way, we’re changing the planet faster than an extinction event that wiped out 2/3 of all land species and nearly 90% of all marine species. Roughly 7 times faster.
Please tell your friends and your representatives that we need to address this now. We’re already close to a quarter of the way there, and the climate system doesn’t change with the flip of a switch. And because of CO2′s long “hang time” in the atmosphere, it will take hundreds of years to straighten out what we’ve already done.
Let me know if you want references, I’ve already typed too long here so I’ve left them out.