Why England is so cold

Not Good. Not Good.:
[Via Grasping Reality with Both Hands: Economist Brad DeLong's Fair, Balanced, and Reality-Based Semi-Daily Journal]

Fish Out of Water:

Daily Kos: Freak Current Takes Gulf Stream to Greenland: An unprecedented extreme in the northern hemisphere atmospheric circulation has driven a strong direct connecting current between the Gulf Stream and the West Greenland current. The unprecedented negativity of the “Arctic Oscillation” and the strong connection of the Gulf Stream with the Greenland current are exceptional events. More exceptional weather events are predicted with anthropogenic climate change, but this could be a natural variation of weather and currents.

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Bad Astronomy sent me to this picture of a frozen Great Britain.

And Greenland is otter than normal. Perhaps now we know why.

Technorati Tags: Environment, Science

Why at least 15 years is necessary

How Long?:
[Via Open Mind]

Time and time again, denialists try to suggest that the last 10 years, or 9 years, or 8 years, or 7 years, or 6 years, or three and a half days of temperature data establish that the earth is cooling, in contradiction to mainstream climate science. Time and time again, they’re refuted — shown [...]

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In order to see any trend when there is a lot of noise, one needs some amount of time. This post provides a very nice discussion of how to determine how much time is needed in order to be sure what the warming trend in global temperatures is.

Relatively simple math shows that at least 15 years is needed for atmospheric temperature trends to be seen above the yearly noise.

That does not mean that there’s been no warming trend in those 15 years — or in the last 10, or 9, or 8, or 7, or 6 years, or three and a half days. It only means that the trend cannot be established with statistical signficance.

The same for any suggestion that there has been cooling over the last decade. Anyone who suggests as much today does not understand how to separate noise from signal.

Technorati Tags: Environment, Science