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).
