Note: While temperatures have risen in the U.S. some one-degree Fahrenheit in the past century, those in Maine have gone up 1.4 degrees and winters have warmed three degrees. On the other side of the continent the changes are even more dramatic. Alaska's temperature has risen 3.4 degrees while its winters have risen 6.4 degrees, bringing in stinging insects (wasps), mosquitoes, and pine bark beetles, all while melting tundra and coastal inundations are forcing communities to relocate, causing untold emotional and mental stress.
Then, to extreme events. Extreme weather events are increasing in frequency and their very nature is intensified by global warming. With the warmed atmosphere holding more water vapor and the warming ocean the repository for the last century's global warming, rain is coming down with increasing intensity across the continual U.S. The yearly amount has increased seven percent overall since 1970, while two-inch/day rains, four-inch/day rains, and six-inch/day rains have increased 14 percent, 20 percent, and 27 percent, respectively. Rains in the U.S. over two-inches/day are associated with E. coli and cryptosporidium infections. Heavy rains and flooding can also spread toxic chemicals and leave new breeding sites for mosquitoes.
Pests and Diseases Affecting Forests, Crops, Marine Life
Pests and diseases affecting forests, crops, and marine life are also encouraged in a warmer world. Bark beetles are over wintering (absent sustained killing frosts) and moving to higher latitudes and altitudes, and getting in more generations each year from Arizona to Alaska. Drought in the west also affects tree resistance, drying the resin in the bark that normally drowns the beetles as they try to drive through.
While bark beetles are a natural part of the ecology of forests, consuming dead stands and
recycling nutrients, warming and extremes have upset this balance, negotiated over millennia, emboldening the pests while weakening the hosts.
Forest health is also threatened in the Northeast U.S. Asian Long-horned beetles could spread with warmer winters. Today, the wooly adelgid -- an aphid-like insect -- is decimating Eastern hemlock trees in New England, altering stream quality, and increasing the potential for wildfires (that cause injury, air pollution, death, and property loss, plus tons of carbon released, and damage to oxygen and clean water supplies.)
Crop pests and diseases are also aided by warming and extremes. Warming increases their potential range, while floods foster fungal growth and droughts favor aphids, locusts, and viral-infecting whiteflies. Higher CO2 stimulates growth of agricultural weeds. The combination of more pests, diseases, and weeds may require more pesticides, herbicides, and fungicides (where available) for control, increasing the chemical threats to human health. Globally, crop pests, pathogens, and weeds take up to 40 percent of yield annually, amounting to some $300 billion in losses on global markets.