TROPICAL RAINFORESTS: Disappearing Opportunities
Questions Over Global Warming
Until recently there was serious debate among scientists, policians, and industry leaders whether the Earth is warming. Now the balance of evidence does indeed suggest global temperatures are increasing, though we are not certain whether this is a temporary fluctuation or an extended trend.Now the focus of the debate has turned to whether global warming is anthropogenic in nature. That is, are humans responsible for most of the recent increase in global mean temperatures or is warming occurring naturally due to a number influences ranging from the solar output of the sun to changes in the tilt of the Earth's axis. There is plenty of evidence supporting both positions on the issue and substantially more research is required before. Until then, it is probably best to play it safe and moderate greenhouse gas emissions.
There are also many questions on how climate increases will develop. Today it is believed that Earth's climate may be relatively "tippy," capable of changing rapidly once a certain threshhold is met. There is also some uncertainty of the feedback systems that may be triggered as warming progresses. For example, as polar ice melts and raises ocean levels, will it increase evaporation and precipitation resulting in glacier growth canceling out polar ice loss? Or will increased forest soil respiration rates increase with carbon dioxide levels and stimulate further warming and forest die-off?
Continued: Extinction