While
playing tennis one sunny afternoon, I began wondering the following: What is
it that makes good climates go bad? That random question passing through my
mind sparked another question: What does it mean to have a “good”
climate? So, I resorted to a Google search on the phrase “good climate.”
In fact the search identified many Web sites with “good climate” in
their text. However, the climate they were referring to almost totally was the
atmosphere for carrying out a good business arrangement — a “good
climate” for studying, working and conducting wide range of activities.
But “climate” specifically is the appropriate environment that allows
for the carrying out of favored activities.
What constitutes good climate is different
to people in different places. Some people are acclimated to the cold Arctic.
Others prefer the hot humid rainforest, such as the jungles in the Peruvian
Amazon. Yet others may live in hot, dry desert climates, like the nomad shown
here traveling along sand dunes of the Sahara Desert, near Erfoud in southern
Morocco. Copyright of AGI.
Eskimos live in cold climate conditions; desert nomads live in hot dry climates;
people in tropical rainforests live in what many people in other ecosystems
would call oppressive humidity and sweltering heat. These populations in their
respective climate regimes may consider their environments to be “good
climate,” but each is very different. And most likely, it would not be
possible to encourage any group to move to the others’ climate setting.
American longshoreman-philosopher Eric Hoffer wrote in his 1963 book Ordeal
of Change about how people fear change. Our grandparents lived through harsh
winters and hot summers, usually without the benefits of heat or air conditioning.
They just did it. Today, we have milder winters and not-so-bad summers. We also
have all the accoutrements of an affluent industrialized society. We wouldn’t
think of moving to a home in Arizona with no air conditioning or to a cabin
in Maine with no heat.
Anything that changes our daily climates would likely cause or will be perceived
as a problem because it would mean we would eventually have to change our behavior
in ways we don’t really know. So arguably, perceptible changes are general
examples of a climate “going bad.” Less rain or more rain for crops,
depending on location, activities and crop type, could also signal a climate
going bad, as could cloudier days, sunnier days, drier days or more humid days
for someone or some activity.
What, then, is a bad climate? It is one in which individuals and ecosystems,
including human settlements, are unable to survive in a sustainable way over
a long period of time. While some individuals may have the fortitude and economic
well-being to move to a more favorable climate, most people do not have that
option. They have to live under the climate regime into which they were born.
To them, the idea of a “good climate” or a “bad climate”
is irrelevant. They live in a tolerable climate, one to which their expectations
and their behavior have become accustomed.
So, there may be climate regimes under which we would like to live and those
under which we do live and tolerate. Visiting a perceived “ideal”
climate is one thing; living in it forever is another. American novelist John
Steinbeck once wrote, “I’ve lived in good climate and it bores the
hell out of me. I like weather rather than climate.”
While we can question what it means to have a good, bad or tolerable climate,
there are real characteristics of a climate that can be measured — temperature,
precipitation, humidity, etc. — and matched to appropriate human activities.
Those characteristics can change at different rates in different locations.
Whether or not humans can adjust to those rates and changes without disruption
will vary from place to place, and from time to time, even in the same place.
The notion of adaptation has now crept into discussions in the past two and
a half decades about global warming (and before then, a decade of talk about
global cooling). At first, discussions centered at the international level on
prevention of those factors that are enhancing the naturally occurring greenhouse
effect. Given the apparent inability of the international community to work
together to freeze the global climate regime the way it is today (which, by
the way, is favorable to some, unfavorable to others and only tolerable to yet
others), “adaptation” became the buzz word.
Prevention versus adaptation frames societal responses as being only black and
white, positive or negative, all or nothing. There are other types of societal
responses, the ones that individuals and societies engage in all the time, so
simple as to be overlooked: adjustment, acclimatization, becoming accustomed
to.
In thinking about our potential responses, however, it is also useful to think
about what shapes our climate. There are many geophysical reasons — including
Earth’s orbit, solar activity, continental drift and volcanism — why
good climates go bad. Such reasons seem to get the lion’s share of the
public’s attention. But perhaps societies and their leaders are all too
eager to blame something or someone else for the damages (death, sickness, misery
and destruction) caused by those anomalies. Human activities from a local to
a national scale can affect the climate regimes under which people operate.
For example, scientists have identified human influences on the climate and
weather of metropolitan areas. They have labeled the results of this influence
as the “urban heat island” effect: The concrete and asphalt surfaces
that dominate metropolitan areas, along with the widespread use of fossil fuels
(coal, oil, natural gas), as well as innumerable heating and cooling systems
in high concentration, has led to the heating up of an invisible bubble of warm
air that encompasses urban areas.
This example shows people altering the climate in the place where they have
chosen to settle. In addition, the heat island can also influence precipitation
within the bubble, with storms, for example, dropping more moisture on metropolitan
areas. The heat island also has impacts downwind in suburban and rural areas,
apparently by increasing precipitation in those areas.
Human activities have also led to major changes in regional climate regimes.
One example of the “foreseeability” of such an impact can be found
in the Amazon basin of South America. Deforestation rates in the basin are quite
high, and cutting down the forest reduces, at an admittedly incremental but
cumulative pace, the rainforest’s effectiveness as a sink for atmospheric
carbon dioxide. Burning the rainforest creates a source of carbon dioxide as
well.
Of more immediate concern, though, is that researchers have found that about
half of the rain that falls in the Amazon basin comes from the rainforest itself
in a self-perpetuating water recycling process. Cutting down trees in the forest
chips away at the amount of precipitation that can be expected to fall within
the basin. This process eventually reduces soil moisture, river-flow quantity
and quality, and even human habitability in the region in ways that can already
be seen around the globe on small scales.
Another
example of regional climate change induced as a result of human activities is
the changing Aral Sea in Central Asia. The Aral Sea was the fourth largest inland
sea in the world as of 1960. Today, it has dropped more than 22 meters and has
separated into two separate seas. Its demise is directly attributable to political
decisions to divert water from the basin’s two major rivers that feed the
sea, and to put that river water on dry but potentially fertile desert soils.
Studies now show that as a result of the desiccation of the Aral Sea and the
resulting increase in exposure of large expanses of the sandy seabed (a change
in land surface reflectivity), the region’s winters have gotten colder
and the summers hotter.
Once the fourth largest lake on Earth,
the Aral Sea moderated Central Asia’s continental climate and supported
a productive fishing industry. It has shrunk dramatically over the past few
decades, as people have diverted the primary rivers that fed the sea for cotton
farming and other agriculture. Landsat satellite imagery (left image) shows
that the northern and southern half of the sea had already become virtually
separated by 1989. The image at right was captured by the Moderate Resolution
Imaging Spectroradiometer on the Aqua satellite on Aug. 12, 2003, and shows
the rapid retreat of the sea’s southern half, now separated into western
and eastern portions. Courtesy of NASA and the University of Maryland Global
Land Cover Facility.
Books have been written about how civilizations have misused their land by deforesting,
over-cultivating, over-irrigating or overgrazing vulnerable ecosystems. North
Africa, for example, was once the granary of the Roman Empire. Some historians
blame the current desert landscape along the southern Mediterranean on deforestation
and on poor land-use practices for cultivation. Others blame it on a major natural
change to the region’s climate regime. Most likely, both were contributing
factors — but in what proportion?
There is also a general belief — some say blind faith — that what
people have done that is bad for the environment or climate, they can undo.
All it will take is engineering know-how and technological innovation. As a
result, throughout history there have been attempts to restore changed climate
conditions to their original state. Climate modification schemes have been proposed
to bring rainfall, for example, back to arid lands where it had once fallen.
The planting of trees has been a popular idea, fostered by European foresters
to bring rain back. Others have hypothesized that rainfall tends to “follow
the plow,” for example, responding to cultivation practices, as well as
tree planting and settlements.
That brings us to the topic of the day (or topic of the century) — global
warming. I do believe that the byproduct of human activities can alter the chemistry
of Earth’s atmosphere in ways that will slowly but profoundly affect societies
worldwide. The emission of greenhouse gases (carbon dioxide, nitrous oxide,
methane and various types of CFCs) to the atmosphere in ever increasing amounts
since the onset of the Industrial Revolution in the mid-1700s has enhanced the
naturally occurring greenhouse effect. The consequence has been the warming
up of the global average temperature by 0.7 degrees Celsius since the beginning
of the 1900s.
While there is controversy over various scientific aspects of the global warming
phenomenon (is it human-induced or is it a natural occurrence?), evidence has
been mounting over the past several decades that human activities are at play
in the heating up of the relatively thin atmosphere that shrouds planet Earth.
But societal leaders and citizens are always on a slippery slope, living within
the bounds of the climate conditions that they have inherited from their predecessors
as well as having to anticipate future variations. Those leaders have to make
decisions about future demands as well as present-day needs for water, energy,
food, public health and safety. They are constantly forced to do so in the absence
of full knowledge of future climate conditions in other locations as well as
their own.
We know that climate varies naturally on a range of time scales from months
to years, decades, centuries and millennia. We need to understand the causes
and effects of those extremes (highs and lows) in variability of temperature
and rainfall; we need to juggle their activities against recurrent but aperiodic
droughts, floods, severe storms and fires, and against quasi-periodic episodes
of El Niño and La Niña.
However, armed only with hazy insights into the future and scientific information
with varying degrees of uncertainty, we end up tracking the climate variability
curves and twists imperfectly. As a result, actions are often taken that prove
to have been inappropriate for any particular unexpected climate anomaly.
Much of this is known. At least at a general level, we are familiar with the
natural factors that affect the planet’s atmospheric composition and behavior
— our climate. We are also becoming increasingly familiar with the actions
that societies take that harm the environment, including the chemistry of the
atmosphere, thereby affecting climate. What seems to have been neglected is
what constitutes a good, bad or tolerable climate.
When we talk of climate change, is it that we fear change — any change
— to the local or global climate conditions to which we have become accustomed?
Or, on a more positive note, is it that we (from Inuit in the Arctic to Tuareg
in the Sahara) consider the climate we have as a “good” climate worthy
of preservation for as long as possible? To what extent do societal climate
preferences match individual climate preferences?
These are important questions to address, as we now know for sure that climates
are constantly changing in both linear and nonlinear ways and that over the
course of life on Earth, organisms have either adjusted to those changes or
perished.
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