Why warm winters are bad for the environment

Paradise Lake at Hidden Valley Lake, Indiana
Paradise Lake at Hidden Valley Lake, IN

Whether or not you agree with the interpretation of worldwide weather data that indicates a climatic warming trend, you have probably seen something locally that indicates that things are changing. For me, that change is the earlier bloom times in buckeye trees over the 28 years that I have lived in HVL.

Why have I noticed this? – my birthday is in early May, and migrating Baltimore orioles first appeared outside my window on that date in 1988 when the buckeyes were in full bloom. Over the years, the trees have bloomed earlier and earlier and now, the flowers have fallen a full month before the orioles migrate to our area. I have not seen or heard those beautiful birds feeding on buckeye flower nectar for the past decade. What changes have you noticed?

You may like the shorter and warmer winters, but there are some potentially negative impacts on other wildlife that will have paybacks in upcoming months. See if you can detect some of these changes this year:

Insects – generally, warmer winters mean that more insects are likely to survive due to lower lethal temperatures. There are too many kinds of insects to make a broad statement, but multigenerational insects have more time to produce offspring, so we will probably experience greater densities of pests like mosquitoes, fleas, and ticks.

Field crops – early emerging insects are physically larger when crops emerge and can cause significant damage to seedlings. Warmer weather can also accelerate fungal infections that impact crops.

Vernalization – Seeds from many native flowering plants require a lengthy period of cold to break seed coats and to trigger germination. Paradoxically, mild winters can decrease the emergence of new plants so native flower populations can be adversely impacted (along with their pollinators). Unfortunately, this does not impact invasive species that are adapted to warmer climates.

Invasive species – We will continue to see an increased spread of invasive species like honeysuckle and garlic mustard since these plants bloom earlier and outcompete the native plants that typically remain dormant longer.

Flowering plants, including fruit trees – early flowering not only puts flower buds at risk of damage from unexpected killer frosts but disturbs the synchronization between the plants and their specific pollinators.

Pollinators, like bees – Early flowering plants like hydrangeas and rhododendrons provide pollen for bees. When these plants bloom early, critical food supplies may have dwindled by the time the female bees emerge from hibernation and further threaten bee populations.

Songbirds – Migration time frames are genetically calibrated to arrive at each new stop just as food supplies – insects and berries – are at their peak. Populations will decrease if food is unavailable when hungry birds reach traditional stopovers.

Bats – Bats that are already endangered by the fungal white nose disease may break hibernation in early January or February and emerge looking for insects that have not yet hatched or matured. Already weakened by the disease, many will starve to death.

Amphibians – Animals like toads overwinter beneath the frost line and require a snow cover to insulate the soil. In a seeming twist of logic, a warmer winter means that amphibians have a higher risk of freezing. Frogs and salamanders begin to breed when temperatures reach 50°F., so there is also a risk to hatchlings with wild temperature swings like we experienced in the last week of February.

So, even if stories of melting ice packs and starving polar bears do not convince you that humans have impacted temperatures worldwide, you should be able to detect that something is going on. Even subtle environmental changes will impact your comfort, food supplies, and enjoyment of the beauty of nature. Do what you can to minimize carbon emissions that are highly correlated to increased temperatures.

Submitted by Linda Hartmann