The upcoming ice age has been postponed indefinitely, headlines this article by John Cook.
27 Jan 10 – “The whole premise of the website Ice Age Now is that a new ice age could begin any day,” says Cook. “Its (sic) time to put all those ice age fears to rest once and for all.”
“Just a few centuries ago, the planet experienced a mild ice age, quaintly dubbed the Little Ice Age,” says Cook.
Not sure why he uses the word “quaintly.” Maybe it’s quaint that millions of people died of starvation during that “mild ice age.”
“Part of the Little Ice Age coincided with a period of low solar activity termed the Maunder Minimum (named after astronomer Edward Maunder),” Cook continues. “It’s believed that a combination of lower solar output and high volcanic activity were a major contributor (Free 1999, Crowley 2001), with changes in ocean circulation also having an effect on European temperatures (Mann 2002).”
Cook then displays a chart showing that solar activity is declining.
“Could we be heading into another Maunder Minimum? asks Cook. “Solar activity is currently showing a long term cooling trend. 2009 saw solar output at its lowest level in over a century.”
So far so good.
Other than using that word “quaintly,” Cook is spot on. But he then wanders off, insisting that “the warming from man-made greenhouse gases far outstrips any potential cooling even if the sun was to return to Maunder Minimum levels.”
And that leads him to what he must consider his most telling argument.
“Our climate has experienced much more dramatic change than the Little Ice Age,” says Cook. “Over the past 400,000 years, the planet has experienced ice age conditions, punctuated every 100,000 years or so by brief warm intervals. These warm periods, called interglacials, typically last around 10,000 years. Our current interglacial began around 11,000 years ago. Could we be on the brink of the end of our interglacial?”
Cook then displays a temperature graph of the past 420,000 years, showing the cyclical nature of ice ages (and warming).
Temperature change at Vostok, Antarctica (Petit 2000). The timing of warmer interglacials is highlighted in green; our current interglacial, the Holocene, is the one on the far right of the graph.
“How do ice ages begin?” asks Cook. “Changes in the earth’s orbit cause less sunlight (insolation) to fall on the northern hemisphere during summer. Northern ice sheets melt less during summer and gradually grow over thousands of years. This increases the Earth’s albedo which amplifies the cooling, spreading the ice sheets further. This process lasts around 10,000 to 20,000 years, bringing the planet into an ice age.”
Again, Cook is spot on. Past changes in climate have indeed been caused by variations in the Earth’s orbit.
Take another look at that chart. See the sharp peaks every 100,000 years or so? Each peak marks the abrupt end of a period of warmth similar to today’s and the catastrophic beginning of a new ice age.
These peaks are caused by a process called orbital stretch – the periodic stretching and shrinking of our elliptical orbit around the sun. (I discuss orbital stretch in Not by Fire but by Ice.)
But don’t worry, that’s not going to happen this time, says Cook. “As things stand now, the combination of relatively weak orbital forcing and the long atmospheric lifetime of carbon dioxide is likely to generate a longer interglacial period than has been seen in the last 2.6 million years.”
“The current interglacial is expected to last another 15,000 years.” says Cook.
Another 15,000 years!
Wait a minute. Take yet another look at the chart. See where we are today? This chart shows that each of those previous interglacials were warmer than today. Warmer!
I thought we were supposed to be enduring “unprecedented” global warming.
Never you mind. This time around, we humans are going to accomplish the impossible. We are going to override orbital stretch! We are going to override a planetary force that has existed for at least 4.6 billion years!
- Can’t Cook see what happened about 420,000 years ago? Temperatures were warmer than today. Did humans cause that period of “global warming”?
- Can’t Cook see what happened about 325,000 years ago? Temperatures were warmer than today. Did humans cause that period of “global warming”?
- Can’t Cook see what happened about 240,000 years ago? Temperatures were warmer than today. Did humans cause that period of “global warming”?
- Can’t Cook see what happened about 120,000 years ago? Temperatures were warmer than today. Did humans cause that period of “global warming”?
- Can’t Cook see that there is a cycle?
- Can’t Cook see that temperatures are now lower than they were just a few thousand years ago?
- Can’t Cook see that we rapidly descended into an ice age after every single interglacial in the past 450,000 years?
- How in the world can he say the world is warming when his own graph shows just the opposite?
- Can’t Cook see why I fear that we are now headed into the next ice age?
See entire article here:
I wrote a similar response to a similar article that appeared on the same website in September 2010. That response was entitled “Website tries to debunk iceagenow – But their own graph proves my point.”