TODAY'S Monitor carries a special report on the increasing political and economic power of the environmental movement in the United States. There are almost 10,000 environmental groups in the US: The 20 largest can raise $1 billion a year. New laws require governments, businesses, and others to spend more than $100 billion a year on pollution control. Most school districts now include environmental studies in their curricula. And politicians at all levels are feeling the influence of an environmentally m otivated public. Vice President-elect Al Gore Jr. is seen as a top environmental spokesman and the Clinton-Gore administration is expected to be especially friendly to the cause. But while business leaders and environmentalists seem to be moving into a new era of cooperation, much remains to be done in the areas of endangered species, toxic-waste disposal, cleaner air and water, and environmental relief for the politically and economically disenfranchised.