Temperature Change

In 1990 a group of scientists led by C. Covey performed a series of computer simulations to determine the effects of asteroid impacts on the earth's climate. Using a sophisticated computer program and the following assumptions (see Assumptions) the global average land surface temperatures following small, medium and large (Alvarez sized) impacts were determined.

The only data associated with the K/T boundary would be the Alvarez Asteroid impact scenario. Recall, it was Walter Alvarez who in 1980 proposed that an asteroid struck the earth causing the loss of life at the K/T boundary (see Asteroid Impact) . The Alvarez Asteroid has variables that are set to match the asteroid that Alvarez concluded hit the earth 65 million years ago.

Following the impact there would have been an abrupt decrease in temperature to around 5 °C (278K). You may be wondering about the immense amount of heat that is caused by an impact. In this simulation it was assumed that the heat would have quickly radiated into space, and so it was not considered in this experiment (see Assumptions). The temperature would have steadily decreased until 9 to 10 days after the impact, when it would have leveled off at around -2 °C (271 K), where it would have remained for at least another 10 days.

The following maps show the conclusions of the O.B Toon experiment: (shaded areas are below freezing, hatched areas are between 0 and 10 °C).

Control Case 30 Day Average

Small Impact Case Days 14-17

Medium Impact Case Days 2.5-5.5

The Alvarez Impact Result Days 10-20

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