North America isn't the only continent that has a temperature shift in its forecast. The Intergovernmental Panel on Climate Change (IPCC) predicts that the entire Northern Hemisphere's temperature gradient - cooler toward the North Pole and warmer towards the equator - will move north. Ticks and mosquitoes will then shift their ranges north. Then, deer and other wildlife will acquire these pests, whereas these populations had been too far north to acquire them before. And the diseases these insects carry will also move north.
For instance, the lone star tick carries a bacterium that causes a rash and fever in humans called ehrlichiosis. In the Unites States, concentrations of cases have moved from Virginia to Massachusetts, according to Rich, and he says this mirrors warming in the northern states. But whether it's erhlichiosis in Maine or malaria in England, the last word on whether we see more cases of the disease with warming will depend on the strength of local health care.
Life & Earth Science, "10 Predictions for Evolution Over the Next Million Years", [online], Available: http://science.discovery.com/life-earth-science/10-predictions-for-evolution.htm