Many people can observe for themselves that their climate
is changing and growing warmer even if they don’t believe the effect is due to
human activity. However, most are yet to
experience a sense of urgency appropriate for what the future holds. Bill McKibben attempts to convey the
seriousness of climate change to those who still haven’t got the message in an
article in The New Yorker: How Extreme Weather Is Shrinking the Planet. It was titled Life on a Shrinking Planet in the paper version. He begins with this lede.
“With wildfires, heat waves, and
rising sea levels, large tracts of the earth are at risk of becoming
uninhabitable.”
The current world population is estimated at about 7.7
billion. Those who make such projections
anticipate population growth leveling off leaving us with a peak population of around
10 billion sometime this century. That
means a lot more people are coming. If
habitable space is declining, there will be problems.
The most obvious source of a shrinking habitat is the
rise in sea levels that are observed.
The potential rise is astounding.
If the Greenland ice cap should melt sea levels would rise by 20
feet. If all of Antarctica melts as well,
that would add another 200 feet. These
eventualities would take a long time to occur, but scientists are eager to make
projections of the seal level rise that could occur by the end of this century,
and they are significant. Jeff Goodell
addressed these estimates in his book The Water Will Come: Rising Seas, Sinking Cities, and the Remaking of the Civilized World and found estimates of peak possible sea rise in that
period between 3 and 15 feet. The more
scientists observe the effects of global warming, the more worried they become
about the rate of ice melt. Even if only
3 feet is encountered, Goodell claims that will be disastrous.
“Globally, about 145 million
people live three feet or less above the current sea level. As the waters rise, millions of these people
will be displaced, many of them in poor countries, creating generations of
climate refugees that will make today’s Syrian war refugee crisis look like a
high school drama production.”
McKibben chimes in to point out that people are already
on the move because of rising sea water. We don’t have to wait long for the effects to
become quite severe.
“Each year, another twenty-four
thousand people abandon Vietnam’s sublimely fertile Mekong Delta as crop fields
are polluted with salt.”
“In one week at the end of last
year, I read accounts from Louisiana, where government officials were
finalizing a plan to relocate thousands of people threatened by the rising Gulf
(‘Not everybody is going to live where they are now and continue their way of
life, and that is a terrible, and emotional, reality to face,’ one state
official said); from Hawaii, where, according to a new study, thirty-eight
miles of coastal roads will become impassable in the next few decades; and from
Jakarta, a city with a population of ten million, where a rising Java Sea had
flooded the streets. In the first days of 2018, a nor’easter flooded downtown
Boston; dumpsters and cars floated through the financial district. ‘If anyone
wants to question global warming, just see where the flood zones are,’ Marty
Walsh, the mayor of Boston, told reporters. ‘Some of those zones did not flood
thirty years ago’.”
A hotter world is close to creating zones where the
combination of high temperature and high humidity will render them uninhabitable.
“About a decade ago, Australian
and American researchers, setting out to determine the highest survivable
so-called ‘wet-bulb’ temperature, concluded that when temperatures passed
thirty-five degrees Celsius (ninety-five degrees Fahrenheit) and the humidity
was higher than ninety per cent, even in ‘well-ventilated shaded conditions,’
sweating slows down, and humans can survive only ‘for a few hours, the exact
length of time being determined by individual physiology’.”
Even higher temperatures are common on the planet, allowing the deadly threshold to fall to lower levels of humidity.
“As the planet warms, a
crescent-shaped area encompassing parts of India, Pakistan, Bangladesh, and the
North China Plain, where about 1.5 billion people (a fifth of humanity) live,
is at high risk of such temperatures in the next half century. Across this
belt, extreme heat waves that currently happen once every generation could, by
the end of the century, become ‘annual events with temperatures close to the
threshold for several weeks each year, which could lead to famine and mass
migration.’ By 2070, tropical regions that now get one day of truly oppressive
humid heat a year can expect between a hundred and two hundred and fifty days,
if the current levels of greenhouse-gas emissions continue.”
Temperatures are rising faster near the poles than at the
lower latitudes leading to severe effects in Alaska. Villages were often built on the coast to
take advantage of the sea ice, but now the sea ice disappears and leaves the
coast vulnerable to erosion during storms.
Entire villages must be moved further inland. The rising temperatures also increase the
melting of permafrost. Buildings were generally constructed on the assumption that
permafrost was permanent. Now that it is
demonstrably not permanent, bad things are happening.
“As the permafrost melts, it
releases more carbon into the atmosphere. The thawing layer cracks roads, tilts
houses, and uproots trees to create what scientists call ‘drunken forests.’
Ninety scientists who released a joint report in 2017 concluded that economic
losses from a warming Arctic could approach ninety trillion dollars in the
course of the century, considerably outweighing whatever savings may have
resulted from shorter shipping routes as the Northwest Passage unfreezes.”
Rising temperatures will also make it more difficult to
feed those extra 2.5 billion people who are expected to arrive. Among other factors, the fundamental process
of photosynthesis is strongly temperature dependent, falling off rapidly at
higher temperatures. This source provides information.
“At medium temperatures, between
50 and 68 degrees Fahrenheit, or 10 and 20 degrees Celsius, the photosynthetic
enzymes work at their optimum levels, so photosynthesis rates gauge high.”
“At temperatures above 68
degrees Fahrenheit, or 20 degrees Celsius, the rate of photosynthesis decreases
because the enzymes do not work as efficiently at this temperature. This is
despite the increase of carbon dioxide diffusion into leaves. At a temperature
above 104 degrees Fahrenheit – 40 degrees Celsius – the enzymes that carry out
photosynthesis lose their shape and functionality, and the photosynthetic rate
declines rapidly.”
McKibben provides this observation.
“The Potsdam Institute for
Climate Impact Research concluded in a recent study that, as the number of days
that reach eighty-six degrees Fahrenheit or higher increases, corn and soybean
yields across the U.S. grain belt could fall by between twenty-two and forty-nine
per cent.”
Rising temperatures increase the amount of water and
energy in the atmosphere. This will lead
to weather events that are more powerful and more destructive. While average global rainfall is likely to
increase, there is no way of knowing where and when it will fall. We are now experiencing a combination of
drought conditions and extreme flooding.
That is expected to get worse, but the locations of those events need
not remain the same.
“As some people flee humidity
and rising sea levels, others will be forced to relocate in order to find
enough water to survive. In late 2017, a study led by Manoj Joshi, of the
University of East Anglia, found that, by 2050, if temperatures rise by two
degrees a quarter of the earth will experience serious drought and
desertification. The early signs are clear: São Paulo came within days of
running out of water last year, as did Cape Town this spring. In the fall, a
record drought in Germany lowered the level of the Elbe to below twenty inches
and reduced the corn harvest by forty per cent…We’ve already overpumped the
aquifers that lie beneath most of the world’s breadbaskets; without the means
to irrigate, we may encounter a repeat of the nineteen-thirties, when droughts
and deep plowing led to the Dust Bowl—this time with no way of fixing the
problem.”
Perhaps the most significant result of global warming
will be conflict. Rising sea levels,
scarcity of food and water, storm damage, and desertification will all create
climate refugees. Hundreds of millions
of people will be forced to move seeking a viable place to live. Humanity’s record for dealing with refugees
does not foster optimism. Mass murder is
the more likely outcome.
Human civilization will likely endure, but it will enter
an uglier, more brutal phase.
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