Invasive Species and Disease

Perhaps one of the most important and deadly consequences of climate change is the effects warming will have on invasive species and the spread of disease.
Invasive species are species which are introduced to an area (e.g. by humans or climate change), are able to survive and breed there and consequently create competition with native species often out competing them.  Invasive species can also been seen as pests, such as certain species of insects, which then eat/damage crops and harm wildlife.  Invasive species can spread disease easily from one area to another - for example mosquitoes and ticks.

Climate change is warming the planet.  Areas that were previously too cold for ticks and mosquitoes to survive in are now warm enough for them to invade.  This will increase in the years to come as temperatures increase globally.  Virus carrying insects are becoming more and more prevalent in areas previously inhabitable [1].  These diseases are likely to affect not only animals but humans as well.  The likelihood of animals viruses being contracted in humans will also increase as the number of different viruses as well as the spread of each increases [2].
Areas as far as the Arctic are set to be affected by the spread of disease.  As Arctic marine temperatures increase, the number of fish pathogens has also increased.  Fish under stress due to warming conditions are more susceptible to these pathogens.  As sea ice reduces, summers become longer and milder.  These new conditions allow increased growth of larvae and parasitic larvae.  Bacteria caused disease, free living viruses and disease brought in by migratory birds are also all set to increase. [3].
The biggest cause of increased disease is change in species range - mostly those of virus carrying insects, ticks and mosquitoes.  There are many factors that counteract the increase in disease carrying insects, however, humans should prepare for more numerous and frequent disease outbreaks in the upcoming future.

References:
[1] http://www.sciencedaily.com/releases/2011/06/110629102150.htm
[2] http://news.bbc.co.uk/1/hi/sci/tech/7657415.stm
[3] Bradley et al (2005), 'The potential impact of climate change on infection diseases of Arctic fauna', International Journal of Circumpolar Health, 64, 468-477.