Climatic Changes Due to
Greenhouse Gases
What is climate change?
The term climate refers to the general weather conditions of a
place over many years. Climate change is a significant variation
of average weather conditions—say, conditions becoming
warmer, wetter, or drier—over several decades or more. It’s
that longer-term trend that differentiates climate change from
natural weather variability. And while “climate change” and
“global warming” are often used interchangeably, global
warming—the recent rise in the global average temperature
near the earth’s surface—is just one aspect of climate change.
How is climate change measured over time?
Earth-orbiting satellites, remote meteorological stations, and
ocean buoys are used to monitor present-day weather and
climate, but it’s paleoclimatology data from natural sources like
ice cores, tree rings, corals, and ocean and lake sediments that
have enabled scientists to extend the earth’s climatic records
back millions of years. These records provide a comprehensive
look at the long-term changes in the earth’s atmosphere,
oceans, land surface, and cryosphere (frozen water systems).
Scientists then feed this data into sophisticated climate models
that predict future climate trends—with impressive accuracy.
What causes climate change?
The mechanics of the earth’s climate system are simple. When
energy from the sun is reflected off the earth and back into
space (mostly by clouds and ice), or when the earth’s
atmosphere releases energy, the planet cools. When the earth
absorbs the sun’s energy, or when atmospheric gases prevent
heat released by the earth from radiating into space (the
greenhouse effect), the planet warms. A variety of factors, both
natural and human, can influence the earth’s climate system.
Natural causes of climate change
As we all know, the earth has gone through warm and cool
phases in the past, and long before humans were around.
Forces that contribute to climate change include the sun’s
intensity, volcanic eruptions, and changes in naturally
occurring greenhouse gas concentrations. But records
indicate that today’s climatic warming—particularly the
warming since the mid-20th century—is occurring much
faster than ever before and can’t be explained by natural
causes alone. According to NASA, “These natural causes
are still in play today, but their influence is too small or they
occur too slowly to explain the rapid warming seen in recent
decades.”
Anthropogenic causes of climate change
Humans—more specifically, the greenhouse gas (GHG)
emissions we generate—are the leading cause of the
earth’s rapidly changing climate. Greenhouse gases play an
important role in keeping the planet warm enough to
inhabit. But the amount of these gases in our atmosphere
has skyrocketed in recent decades. According to the
Intergovernmental Panel on Climate Change (IPCC),
concentrations of carbon dioxide, methane, and nitrous
oxides “have increased to levels unprecedented in at least
the last 800,000 years.” Indeed, the atmosphere’s share of
carbon dioxide—the planet’s chief climate change
contributor—has risen by 40 percent since preindustrial
times. The burning of fossil fuels like coal, oil, and gas for
electricity, heat, and transportation is the primary source of
human-generated emissions. A second major source is
deforestation, which releases sequestered carbon into the
air. It’s estimated that logging, clear-cutting, fires, and other
forms of forest degradation contribute up to 20 percent of global
carbon emissions. Other human activities that generate air
pollution include fertilizer use (a primary source of nitrous oxide
emissions), livestock production (cattle, buffalo, sheep, and
goats are major methane emitters), and certain industrial
processes that release fluorinated gases. Activities like
agriculture and road construction can change the reflectivity of
the earth’s surface, leading to local warming or cooling, too.
Though our planet’s forests and oceans absorb greenhouse
gases from the atmosphere through photosynthesis and other
processes, these natural carbon sinks can’t keep up with our
rising emissions. The resulting buildup of greenhouse gases is
causing alarmingly fast warming worldwide. It’s estimated that
the earth’s average temperature rose by about 1 degree
Fahrenheit during the 20th century. If that doesn’t sound like
much, consider this: When the last ice age ended and the
north-eastern United States was covered by more than 3,000
feet of ice, average temperatures were just 5 to 9 degrees
cooler than they are now.
The effects of global climate change
According to the World Economic Forum’s 2016 Global Risks
Report, the failure to mitigate and adapt to climate change will
be “the most impactful risk” facing communities worldwide in
the coming decade—ahead even of weapons of mass
destruction and water crises. Blame its cascading effects: As
climate change transforms global ecosystems, it affects
everything from the places we live to the water we drink to the
air we breathe.
Extreme weather
As the earth’s atmosphere heats up, it collects, retains, and
drops more water, changing weather patterns and making wet
areas wetter and dry areas drier. Higher temperatures worsen
and increase the frequency of many types of disasters,
including storms, floods, heat waves, and droughts. These
events can have devastating and costly
consequences, jeopardizing access to clean drinking water,
fueling out–of-control wildfires, damaging property, creating
hazardous-material spills, polluting the air, and leading to loss
of life.
Dirty air
Air pollution and climate change are inextricably linked, with
one exacerbating the other. When the earth’s temperatures
rise, not only does our air gets dirtier—with smog and soot
levels going up—but there are also more allergenic air
pollutants such as circulating mold (thanks to damp conditions
from extreme weather and more floods) and pollen (due to
longer, stronger pollen seasons).
Health risks
According to the World Health Organization, “climate change is
expected to cause approximately 250,000 additional deaths per
year” between 2030 and 2050. As global temperatures rise, so
do the number of fatalities and illnesses from heat stress,
heatstroke, and cardiovascular and kidney disease. As air
pollution worsens, so does respiratory health—particularly for
the 300 million people living with asthma worldwide; there’s
more airborne pollen and mold to torment hay fever and allergy
sufferers, too. Extreme weather events, such as severe storms
and flooding, can lead to injury, drinking water contamination,
and storm damage that may compromise basic infrastructure or
lead to community displacement. Indeed, historical models
suggest the likelihood of being displaced by a disaster is now
60 percent higher than it was four decades ago—and the
largest increases in displacement are driven by weather- and
climate-related events. (It’s worth noting that displacement
comes with its own health threats, such as increases in urban
crowding, trauma, social unrest, lack of clean water, and
transmission of infectious diseases.) A warmer, wetter world is
also a boon for insect-borne diseases such as dengue fever,
West Nile virus, and Lyme disease.
Rising seas
The Arctic is heating twice as fast as any other place on the
planet. As its ice sheets melt into the seas, our oceans are on
track to rise one to four feet higher by 2100, threatening coastal
ecosystems and low-lying areas. Island nations face particular
risk, as do some of the world’s largest cities, including New
York, Miami, Mumbai, and Sydney.
Warmer, more acidic oceans
The earth’s oceans absorb between one-quarter and one-
third of our fossil fuel emissions and are now 30 percent more
acidic than they were in preindustrial times.
This acidification poses a serious threat to underwater life,
particularly creatures with calcified shells or skeletons like
oysters, clams, and coral. It can have a devastating impact
on shellfisheries, as well as the fish, birds, and mammals that
depend on shellfish for sustenance. Rising ocean
temperatures are also altering the range and population of
underwater species and contributing to coral bleaching
events capable of killing entire reefs—ecosystems that support
more than 25 percent of all marine life.
Greenhouse Effect
The greenhouse effect is a good thing. It warms the planet to its
comfortable average of 59 degrees Fahrenheit (15 degrees
Celsius) and keeps life on earth, well, livable. Without it the
world would be a frozen, uninhabitable place, more like Mars.
The problem is, mankind’s voracious burning of fossil fuels for
