New research found that more than 22% of native pollinators in North America are at an elevated risk of extinction.

Because of climate ... change chronology that, in some cases, can track back as far as 262 AD. Evidence from ancient Mongolian trees has so far matched data from tree rings in North America ...

Some theories suggest that changes in ocean circulation due to natural variations of North ... Global Climate Change at Millennial Timescales, eds. P. U. Clark et al. (Washington, DC: American ...