Evolution is again being thrown off its usual course, not by collision with an asteroid as suspected long ago but by change in global temperature and the insatiable demands of many species and destruction of their habitats.
The result is rates of extinction several thousand times beyond normal levels. Biological diversity—the varieties, not just the species– of genes and ecosystems is diminishing at precipitous rates throughout the world. Species are vanishing most rapidly and most notably from dwindling tropical forests.
Mass extinction is everywhere: amphibians are declining worldwide; three quarters of the world’s species of birds are vanishing and, genetic varieties of crops, fish and livestock are rapidly disappearing near and far from the equator.
The number of the earth’s lifeforms threatened with extinction has increased, the world’s global watchdog of flora and fauna International Union for the Conservation of Nature (IUCN) said in its September 2018 report.
IUCN bared in its latest Red List that an additional 26,000 species are threatened with extinction today, out of the 27% of all assessed species worldwide.
Of the number, 41 percent are amphibians, 5 percent mammals, 34 percent conifers, 13 percent birds, 31 percent sharks and manta rays, 33 percent corals, and 27 percent selected crustaceans.
Yet, the worst still lies ahead. If human-generated global warming comes to pass as rapidly as climatologists predict, another wave of extinctions—even more massive than the one already in progress– is in store. While the problem of declining biodiversity and global warming have each attracted extensive attention, the relationship between them has not.
With a rapidly changing climate, it is not an understatement to say that practically all habitats on the planet is at risk. More species will face the risk of either adapting or relocating; many will fail to make the transition.
Many regions, instead of simply having their native ecosystems replaced with warmth-oriented ones, may be impoverished biologically—their native species gone but replacements unable to move in fast enough or unable to cross man-made barriers.
Extinction Will Reach Point of No Return
What exactly will happen to the coastal wetland of the Philippines or the fish stocks of Indonesia or the grizzly bears of the Rocky Mountains of USA as the earth warms up? For most species and habitats which have dealt with changing conditions for eons, the warming itself is less a concern than the rate at which it is likely to occur. That in turn depends on how fast humans add heat-trapping gasses to the atmosphere.
A study, published Aug. 30, 2018 in the journal Earth System Dynamics. led by scientists in the United Kingdom and Netherlands, claims that by 2035, we will cross a point of no return — after which it will be extremely unlikely we can stop Earth’s temperature from rising by 2 degrees Celsius (3.6 degrees Fahrenheit) and kicking off a dangerous medley of global disasters especially mass extinctions of species.
“The ‘point of no return’ concept has the advantage of containing time information, which we consider very useful to inform the debate on the urgency of taking climate action,” Matthias Aengenheyster, a doctoral researcher at Oxford University and the study’s lead author, said..
The 2 degrees Celsius mark is critical for Earth’s well-being. Once the planet warms an additional 2 degrees Celsius, scientists predict a range of catastrophic effects, from widespread flooding in coastal areas to searing heat waves and extreme storms.
One important area that could slow the movement toward a point of no return in 2035 is the transition from fossil fuels to renewable energy sources. But even this will require marked progress. Scientists have calculated that the share of renewable worldwide must grow by at least 2 percent each year in order to slow the march toward climate change. Two percent a year may not sound like much, but in the 20 years leading up to 2017, the percentage of energy from renewables grew by a paltry total of 3.6 percent.
There is hope, though. If the use of renewable energy were to outpace the scientists’ model, say by 5 percent per annum, the climate change deadline could move back by at least a decade, the researchers note. Likewise, developing technology to remove carbon dioxide and other gases from the atmosphere could help slow climate change. These gases alter Earth’s atmosphere and allow it to trap more heat from the sun and cause temperatures to rise.
“We hope that ‘having a deadline’ may stimulate the sense of urgency to act for politicians and policy makers,” Henk Dijkstra, a professor at Utrecht University in the Netherlands and one of the study authors, said “Very little time is left.”
Natural Communities Will be Forced to Migrate Away
As oceanic temperatures rise, seas will expand and many marine biologists say its impact on biological diversity becomes less predictable but surely, many species will migrate away from the equator or up from sea level if they are to keep with the shifting climate conditions.
While scientists have developed sophisticated computer models of the global atmosphere, no such models exist to describe the intricate workings of natural ecosystems. Scientists cannot state how many species exist on the planet, let alone describe their interrelationships or predict their reactions to abrupt climate change.
But by studying past changes in climate, pollen and fossil rocks, geography specialists Joanna Ellison and David Stoddart of the University of California have been able to piece information on human-caused climate change assault impacts.
A rapidly warming world will be hostile, vegetation zones will be displaced in the world’ middle latitudes, 200 miles away from the equator or in the mountainous regions 1,800 ft higher in altitude. Tree species in North America will move away, while large-scale die-back of forests will occur for beech, oak and deciduous trees,
To the north, boreal forests will be killed off, coastal habitats will migrate along rising tides, mangrove ecosystems will be stressed, the future of swamps, coastlines and fisheries will not be good the scientists said.
Habitats hemmed by barriers such as mountain ranges and steep coastlines will be unable to move, island species will be unable to escape across the surrounding ocean and lake and river species unable to disperse across the land. These species are especially at risk since they will have to survive climate change in place.
Habitats atop mountains and toward the edges of the continents will also feel the squeeze as conditions favoring lowland or temperate zone species spread, upland and sub Arctic habitats whose plants are already threatened.
Given the overwhelming effects of global warming on already tattered ecosystems, long term biological conservation will be impossible without rapid reductions of greenhouse gas emissions,
Only by making diversity a concern of all landscapes, from the wild to the urban, can the inevitable migration of species and communities be accommodated and the options to deal with unpredictable change, be retained.
By helping nature maintain its ability to adapt we also give ourselves a better shot at weathering the overheated decades ahead.