WASHINGTON — The harmful effects of global warming on daily life are already showing up, and within a couple of decades hundreds of millions of people won’t have enough water, top scientists will say next month at a meeting in Belgium. At the same time, tens of millions of others will be flooded out of their homes each year as the Earth reels from rising temperatures and sea levels, according to portions of a draft of an international scientific report obtained by The Associated Press. Tropical diseases like malaria will spread. By 2050, polar bears will mostly be found in zoos, their habitats gone. Pests like fire ants will thrive. For a time, food will be plentiful because of the longer growing season in northern regions. But by 2080, hundreds of millions of people could face starvation, according to the report, which is still being revised. The draft document by the authoritative Intergovernmental Panel on Climate Change focuses on global warming’s effects and is the second in a series of four being issued this year. Written and reviewed by more than 1,000 scientists from dozens of countries, it still must be edited by government officials. […]