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Will Dixie Become A New Africa?

Climate change is turning the American South into the tropics as flora and fauna change! Are we ready to tackle the problems of Brazilian pepper trees, Cuban tree frogs and Burmese pythons?

The change is likely to result in some temperate zone plant and animal communities found today across the southern U.S. being replaced by tropical communities. These changes will have complex economic, ecological and human health consequences, a new study predicts. As climate change reduces the frequency and intensity of killing freezes, tropical plants and animals that once could survive in only a few parts of the U.S. mainland are expanding their ranges northward, a new U.S. Geological Survey-led study has found


Some effects are potentially beneficial, such as expanding winter habitat for cold-sensitive manatees and sea turtles; others pose problems, such as the spread of insect-borne human diseases and destructive invasive species. The researchers found that a number of tropical plant and animal species are enlarging their ranges to the north. They include insects, fish, reptiles, amphibians, mammals, grasses, shrubs and trees. Among them are species native to the U.S. such as mangroves, which are tropical salt-tolerant trees, and snook, a warm water coastal sport fish, and invasive species such as Burmese pythons and buffelgrass.


In the study published this month in Global Change Biology, a team of 16 scientists who have studied the effects of killing freezes describe how many cold-sensitive tropical plants and animals are kept in check by temperate zone winter cold snaps. Warming winters allow these organisms to spread north, especially into the eight subtropical U.S. mainland states: Florida, Alabama, Mississippi, Louisiana, Texas, New Mexico, Arizona and California.


Most climate change studies focus on changes in mean temperature rather than changes in the highest highs and lowest lows, so the powerful effects of extreme cold snaps on ecosystems are poorly understood, according to USGS research ecologist Michael Osland, the study’s lead author.


“Extreme cold events are critically important in limiting the spread of tropical species because a short spell of intense cold can kill cold-sensitive plants and animals,” Osland said. “So tropical species can only spread to places where they never encounter killing cold temperatures. But as the climate changes, extreme cold events are expected to become rarer, shorter-lasting, and less intense in parts of the temperate zone. And that opens up new territory for cold-sensitive plants and animals.”


As the climate warms, several species of flora and fauna have been documented to be migrating up to higher altitudes at mountainsides in areas like the Rocky Mountains in the United States to escape rising air temperatures.


Now research shows that in the southern part of the U.S. several tropical species of plants and animals are extending their range northward and not all of them will be welcome in their new territories. Disease-carrying mosquitos and destructive invasive species such as Burmese pythons are making the transition up north as well, raising the risk that they will be posing a threat to people and wildlife there. The variety of tropical species that are expanding their ranges northward include native mangroves and some warm-water fish, in addition to invasive species such as Cuban tree frogs, Brazilian pepper trees and buffelgrass.


Soon we will see rainy seasons instead of winters as the return times become longer and longer for extreme cold events, this enables tropical species to get more and more of a foothold, and even for populations to adapt in time allowing them to tolerate more cold extremes in the future,” scientists say. The population will change s well since we show no slowing down when it comes to reaching climate tipping points. Tipping points are climate events that create situations like mean temperature and changing weather patterns that are irreversible.


From our understanding of evolution, populations evolve over time to have specific (advantageous) features because individuals without those features die off and aren’t able to reproduce etc. Such as the thin nose of Europeans to keep warm air rather than cold going toward the brain or wider noses of people from the tropics to keep air cool going toward the brain. Based on this “survival of the fittest” logic:


If biological protection from the increasing amounts of UV rays in a hotter world (assuming a hotter Earth receives larger amounts of UV radiation from the sun) is crucial for human survival, then yes people will become darker-skinned over time. But that would only be because the lighter-skinned people died off or for some reason like photolysis or reduction of sperm count couldn’t reproduce, and so only the darker-skinned people were left. Not because an individual’s skin evolved to produce more melanin within their lifetime- but because natural selection will make the partners with greater chance of survival more likely to mate and promulgate the species, that's just how evolution works. Obviously that’s a very barbaric and inhumane scenario. In modern times It is probable that evolution (via survival of the fittest) has practically no effect on how human societies change.


We can devise technology to adapt us to our environment in ways our bodies aren’t equipped to (a la sunscreen),solar and wind energy providing air conditioning, etc. We have the capacity for empathy, and generally aren’t going to leave people to die just because they aren’t biologically “adapted to the environment” So yes people getting darker as considered is theoretically possible, but based on the reasons outlined unless we continue to damage our ecosystems with fuels that increase global warming most of us are probably safe.


Somewhat encouragingly, however, the scientists note that their findings don’t mean that “we are heading for an extinction of absolutely everything” in northern regions, “But we need to prepare for widespread shifts in the distribution of biodiversity as climate, including winter climate, changes,”

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