Another popular theory the greenhouse effect theory first proposed by Dewey McLean. He and many others believed that a intense period of volcanic eruption and small asteroid impact was the cause however Mclean believed this was a minor event and what followed was the result of the extinction of the dinosaurs.
Mclean says that the asteroid that formed the Chicxulub crater happed 300,000 years before the death of the dinosaurs. According to Mclean the fateful dinosaur killer happed somewhere else on earth and is still yet to be discovered.
Food Chain Destroyed
Dewey McLean agrees with Walter Alvarez’s theory that the asteroids debris and fires would have blocked out the suns rays resulting in what was later know as the ‘Impact Winter’ The earth would have been dark and cold. The cold winter climate would have been to unnatural for the plants (producer) to grow, plants were extremely important, Plants actually changed the chemical makeup of the Earth’s atmosphere by giving off oxygen and absorbing carbon dioxide. They also contributed to erosion and the creation of soil.
Also, since plants are stationary, they determine where plant-eating animals live. An example of a common plant would be a ‘Horsetail’ plant show on the left. If plants such as this on died then there would be no food to keep the Herbivores alive such as triceratops (Primary consumer). With dinosaurs such as these ones dieing their would have been no food for The Carnivores Like the T-Rex (Secondary Consumer) however in McLean’s Opinion this was a minor incident he believes this was just the beginning at it was what followed this event that that killed of the Dinosaurs
Mclean believed that the excess carbon dioxide from the eruptions in the atmosphere would have permitted the sun’s heat into the earth’s atmosphere, but would have blocked most of the heat from exiting the earth’s surface back into space. This would have created a “greenhouse effect”, the increase in temperature could have killed the tiny plankton responsible for converting most of the earth’s carbon dioxide into oxygen which would further compound the problem. Only a few degrees increase in the temperature can affect the fertility of an animal by affecting their ability to produce fertile sperm. Mclean Believes that this was the deciding factor that killed of that dinosaurs and not the asteroid.
Dewey Mclean was famous scientist born is San Antonio Texas he later mover to California like Alvarez to study his profession Geology. He did not win a Noble prize but Won many other reward for his discovery’s in both Dinosaurs and Global Warming. He linked to two together to make his theory.