The Missing Link in Climate Change? → Washingtons Blog
The Missing Link in Climate Change? - Washingtons Blog

Monday, March 30, 2009

The Missing Link in Climate Change?

New York Times bestselling author Gregg Braden claims that climate change is largely driven by the strength of the Earth's magnetic shield at any point in time.

Only a couple of months ago, NASA discovered an unprecedented breach in the Earth's magnetic shield (watch the NASA video), and the strength of the magnetic shield is known to vary in intensity over geologic time. So this is an interesting claim.

However, two NASA scientists explain that the strength of the magnetic shield does not have much effect on climate, as shown in the following question and answer exchange:
My question to you is whether anyone has ever attempted to correlate the Earth's magnetic field strength with climate changes. My layman's logic wonders whether a reduction in field strength of 10% would result in some additional solar energy reaching the atmosphere, and hence cause an increase in overall global temperatures. I understand that the geologic record of magnetic field strength may span far more time than the records of global temperature in the polar ice core samples (or however those estimates are made), but has any attempt at correlation of the data been made?


The "solar energy" received by Earth presumably includes sunlight and the solar wind (with the magnetic effects it brings with it). Let us compare.

Suppose the Earth had NO magnetism at all, so that the solar wind would hit its surface directly--as it hits the Moon, most of the time. The solar wind has a density of about 6 protons per cc, and velocity about 400 km/sec, so each square centimeter facing it is hit each second by as many protons as are in a column about 400 kilometers high and of 1 square centimeter cross section:

400,000 x 100 x 6 = 2.4 x 100,000,000 protons and each square meter (10,000 times larger) about 2.4 1012 protons

Each proton carries about 1000 electron volts, each of which is abut 1.6 10–19 joule So that each square meter gets about 4 10–4joules per second, that is, 0.0004 watt.

The "solar constant" of sunlight energy received by a square meter on the Earth perpendicular to sunlight is about 1300 watt. It's more than a million times larger.

The changing strength of the Earth's magnetic field may have less effect than its magnitude suggests. That field diverts the solar wind around the Earth, though some energy is transmitted in other ways, through reconnected field lines. If the field were only half as strong, the obstacle would be smaller, but still, most of the solar wind would flow around. The total effect remains roughly the same as before--that sunlight is more than a million times more effective as carrier of energy.

Any scientists wishing to weigh in on this question can comment below.

1 comment:

  1. We've long known magnetic fields have effects on climatology. Unfortunately, in our political power plays, we've abandoned the science. Both the formation of the ozone layer, and the destruction of it lay fairly nearby, in the sun. In effect, our magnetic field acts as a solar dynamo, trapping charged particles at the edge of the aurora and both creating and destroying the ozone in a cycle.

    Our solar magnetosphere operates in a very similar method with interstellar hydrogen and other particles. In theory, there should be a charged cloud close to the magnetic poles of the sun, which should give measurable x-ray and microwave radiation at the pole swaps as the field disconnects and reconnects.

    It's pretty incredible with the amounts of energy we're dealing with, and how little we understand it.

    This particular blast made major energy contributions to the ionosphere. This isn't so strange, when you consider the upper atmosphere to be a surface being stripped of electrons, yielding a positive net charge, separated from the 'ground source' via a capacitance layer. (the atmosphere, which is a strong dielectric).

    Stuff I've been looking at for years.


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