It’s the season for frightening ghouls so let me tell you about a couple little bloodsuckers that scare me.

As the climate warms, the home range for the mosquitoes Aedes aegypti and Aedes albopictus is moving north, and with them we can expect to see more of the untreatable viral diseases they transmit. Dengue fever, yellow fever, chikungunya and zika cause untold human suffering throughout the tropical world, and the societal costs in lost revenue and health care are staggering.

Indeed, these and other “tropical” diseases are largely responsible for the dire financial situation in many developing countries.

How did we get to a point in snowy Minnesota where we have to think about tropical diseases? Climate change, that’s how.

Even slightly warmer winters and an earlier spring foster increases in mosquito numbers, expand their geographic range and accelerate the development of infectious organisms within the host mosquitoes.

Furthermore, modern transportation means people and foodstuffs can travel hundreds of miles in a day. So it is only a matter of time before virus meets host insect, who in turn feeds on unsuspecting Minnesotan human lounging lakeside.

Fevers, malaise, headaches and joint pain ensue; local physicians, at first mystified, soon realize they need to bone up on their tropical medicine. We need to prevent this scenario becoming a reality.

Aside from warmer average temperatures, climate change means an increase in severe weather events. Flooded sewage systems and overcrowding due to home and infrastructure damage lead to emergence of food- and water-borne illnesses.

Salmonella, shigella, campylobacter, yersinia, leptospirosis and typhus are not words you ever want to see on your test results. These pathogens cause prolonged illness and even death in vulnerable populations like the very young, old, or immunocompromised. Virtually any major flooding event you care to review will have been associated with upticks in these food- and water-borne illnesses.

Infection is by no means the only health risk associated with climate change. To protect our health, our peace and our economy we need to work furiously hard now with the rest of the world on new technologies, strategies and attitudes to minimize our dependence on carbon-based fuels.

The good news is that more politicians, policymakers and leaders of industry are signing on to make a difference. You can, too: by speaking to your representatives, by joining your local chapter of climate activists and by supporting legislation designed to let renewable energy fulfill its potential as a job-creating economic driver and climate change solution.

Mark Cannon is a local practicing infectious diseases physician and former laboratory virologist.