Changes in the hydrologic cycle, including droughts and flooding, are among the most immediate projected consequences of global warming for human society.

Scientists, including Ken Caldeira of the Carnegie Institution's Department of Global Ecology, have found that the Earth's global warming, 55 million years ago, may have resulted from the climate's high sensitivity to a long-term release of carbon.

The effects of climate change appear in the Arctic before becoming apparent in other regions.

The Global Climate Observing System, an organization sponsored by the World Meteorological Organization, is launching an initiative to provide vital climate information for development needs in Africa. Lisa Schlein reports for VOA from Geneva.

Just as overconfidence in a teenager may lead to unwise acts, overconfidence in projections of climate change may lead to inappropriate actions on the parts of governments, industries and individuals, according to an international team of climate researchers.