These measurement provide a good geologic time scale of atmospheric carbon dioxide levels but they only provide information on carbon dioxide. The last issue of concern is that we do not have a controlled experiment. Because there is not another planet that is a control, it is difficult to know that the effect we are seeing is only due to increases in the greenhouse gasses. To compensate for this lack of control planet, we extrapolate from information we have gained from Venus. Discuss how the lack of biodiversity will adversely impact the world's ecosystems.
Biodiversity increases the ability of an ecosystem to withstand environmental change.
If climate changes, the amount of UV from the sun changes, etc., ecosystems that contain a high level of diversity are more able to tolerate disturbances. It is likely that one or many species will exist within a diverse ecosystem that can survive changes that occur. Erosion, population explosions, etc are less likely in a diverse, complex ecosystem. If one ecosystem lacks biodiversity, no particular problem arises. When many ecosystems are simlified and biodiversity is lost, the ability of the more complex ecosystems to support the simplier ones is compromised.