Heliophage


Green view
January 13, 2010, 10:14 pm
Filed under: Uncategorized

The Economist has a weekly online environment column called Green.view. Here’s a taster of what’s been up there in the past month.

This week, there’s a piece about the current cold weather, what it means, and what it doesn’t mean

One possible implication is a change in the prospects of the current poster child for climate change—Arctic sea ice. The extent of summer ice in the Arctic Ocean has been decreasing at a rate of about 8% per decade. In 2007, as the result of prior losses, peculiar sunniness in some areas and a particular disposition of winds, the ice levels fell spectacularly. That particular alignment of circumstances did not hold sway over the following years, which accordingly saw the ice bounce back somewhat. The current cold in mid latitudes might, counterintuitively, reverse that trend and reduce the ice cover further.

The atmosphere cannot make heat, or even hold that much of it. There is more heat stored in the top four metres of the oceans than in all the Earth’s atmosphere. So when the atmosphere cools down one part of the globe, it is a good rule of thumb that it is warming some other part. In the case of the current mid-latitude chill, it is the high latitudes that are seeing the warming. In Greenland and the Arctic Ocean, December was comparatively balmy. The air above Baffin Bay and the Davis Strait was 7ºC warmer than usual (though that still left it pretty cold).

Last week, we saw in the new year (and sort-of-decade) with a piece about a proposal to add some more time to the beginning of earth history

Rocks from 3.8 billion years ago to 2.5 billion years ago are assigned to the Earth’s earliest geological eon, the Archaean. Anything earlier—a few lumps of Greenland and Canada, and rock-residues preserved now only as inclusions in larger, later, rocks—are referred to as belonging to the Hadean, an informal and ill-defined but useful and evocative term.

The new proposal suggests not just that the Hadean should be formalised, but also that a new aeon, the Chaotian, should be recognised as extending extend further back in time than the Earth itself. The Chaotian would begin with the beginning of the cloud’s collapse, be punctuated in the middle with the ignition of the sun and come to an end with the collision that created the Earth-moon doublet in its sort of modern form. In a fit of further distinctions, the authors—Colin Goldblatt, a young researcher at NASA’s Ames Research Centre, and three older colleagues with considerable previous form in the framing of provocative hypotheses—suggest the Nephelean and Erebrean for the periods before the sun’s ignition, the Hyperitian and Titanomachean for those after.

And back in 2009, a look at the gap between the emissions that are reported and the levels of greenhouse gas that are measured.

ONE of the many sets of initials being bandied about at the climate conference in Copenhagen is MRV—monitoring, reporting and verification. In theory, it seems fairly straightforward: if countries commit themselves to limiting the production of particular greenhouse gases, they need to be able to keep track of what they are doing and to tell the rest of the world, which must in turn be able to verify the claims. In practice, there are any number of problems, one of which is that when you start to look at what is actually happening in the atmosphere, it does not necessarily resemble anything that is being reported. Countries therefore commit themselves to actions without any real idea of the current state of play. As Ray Weiss of the Scripps Institute of Oceanography put it at one of the many side events surrounding the negotiations on the Kyoto protocol and its eventual successor, it is like going on a diet without weighing yourself.

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