Global Warming Myths and Facts
MYTH: The science of global warming is too uncertain to act on.
FACT: There is no debate among scientists about the basic facts of global warming.
The most respected scientific bodies have stated unequivocally that
global warming is occurring, and people are causing it by burning
fossil fuels (like coal, oil and natural gas) and cutting down forests.
The U.S. National Academy of Sciences, which in 2005 the White House
called "the gold standard of objective scientific assessment," issued a
joint statement with 10 other National Academies of Science saying "the
scientific understanding of climate change is now sufficiently clear to
justify nations taking prompt action. It is vital that all nations
identify cost-effective steps that they can take now, to contribute to
substantial and long-term reduction in net global greenhouse gas
The only debate in the science community about global warming is
about how much and how fast warming will continue as a result of
heat-trapping emissions. Scientists have given a clear warning about
global warming, and we have more than enough facts — about causes and
fixes — to implement solutions right now.
MYTH: Even if global warming is a problem, addressing it will hurt American industry and workers.
FACT: A well designed trading program will harness American
ingenuity to decrease heat-trapping pollution cost-effectively,
jumpstarting a new carbon economy.
Claims that fighting global warming will cripple the economy and
cost hundreds of thousands of jobs are unfounded. In fact, companies
that are already reducing their heat-trapping emissions have discovered
that cutting pollution can save money. The cost of a comprehensive
national greenhouse gas reduction program will depend on the precise
emissions targets, the timing for the reductions and the means of
implementation. An independent MIT study found that a modest
cap-and-trade system would cost less than $20 per household annually
and have no negative impact on employment.
Experience has shown that properly designed emissions trading
programs can reduce compliance costs significantly compared with other
regulatory approaches. For example, the U.S. acid rain program reduced
sulfur dioxide emissions by more than 30 percent from 1990 levels and
cost industry a fraction of what the government originally estimated,
according to EPA. Furthermore, a mandatory cap on emissions could spur
technological innovation that could create jobs and wealth. Letting
global warming continue until we are forced to address it on an
emergency basis could disrupt and severely damage our economy. It is
far wiser and more cost-effective to act now.
MYTH: Water vapor is the most important, abundant
greenhouse gas. So if we’re going to control a greenhouse gas, why
don’t we control it instead of carbon dioxide (CO2)?
FACT: Although water vapor traps more heat than CO2, because of the relationships among CO2, water vapor and climate, to fight global warming nations must focus on controlling CO2.
Atmospheric levels of CO2 are determined by how much
coal, natural gas and oil we burn and how many trees we cut down, as
well as by natural processes like plant growth. Atmospheric levels of
water vapor, on the other hand, cannot be directly controlled by
people; rather, they are determined by temperatures. The warmer the
atmosphere, the more water vapor it can hold. As a result, water vapor
is part of an amplifying effect. Greenhouse gases like CO2
warm the air, which in turn adds to the stock of water vapor, which in
turn traps more heat and accelerates warming. Scientists know this
because of satellite measurements documenting a rise in water vapor
concentrations as the globe has warmed.
The best way to lower temperature and thus reduce water vapor levels is to reduce CO2 emissions.
MYTH: Global warming and extra CO2 will actually be beneficial — they reduce cold-related deaths and stimulate crop growth.
FACT: Any beneficial effects will be far outweighed by damage and disruption.
Even a warming in just the middle range of scientific projections
would have devastating impacts on many sectors of the economy. Rising
seas would inundate coastal communities, contaminate water supplies
with salt and increase the risk of flooding by storm surge, affecting
tens of millions of people globally. Moreover, extreme weather events,
including heat waves, droughts and floods, are predicted to increase in
frequency and intensity, causing loss of lives and property and
throwing agriculture into turmoil.
Even though higher levels of CO2 can act as a plant fertilizer under some conditions, scientists now think that the "CO2
fertilization" effect on crops has been overstated; in natural
ecosystems, the fertilization effect can diminish after a few years as
plants acclimate. Furthermore, increased CO2 may benefit undesirable, weedy species more than desirable species.
Higher levels of CO2 have already caused ocean
acidification, and scientists are warning of potentially devastating
effects on marine life and fisheries. Moreover, higher levels of
regional ozone (smog), a result of warmer temperatures, could worsen
respiratory illnesses. Less developed countries and natural ecosystems
may not have the capacity to adapt.
The notion that there will be regional “winners” and “losers” in
global warming is based on a world-view from the 1950’s. We live in a
global community. Never mind the moral implications — when an
environmental catastrophe creates millions of refugees half-way around
the world, Americans are affected.
MYTH: Global warming is just part of a natural cycle. The Arctic has warmed up in the past.
FACT: The global warming we are experiencing is not natural. People are causing it.
People are causing global warming by burning fossil fuels (like oil,
coal and natural gas) and cutting down forests. Scientists have shown
that these activities are pumping far more CO2 into the atmosphere than was ever released in hundreds of thousands of years. This buildup of CO2 is the biggest cause of global warming. Since 1895, scientists have known that CO2
and other greenhouse gases trap heat and warm the earth. As the warming
has intensified over the past three decades, scientific scrutiny has
increased along with it. Scientists have considered and ruled out
other, natural explanations such as sunlight, volcanic eruptions and
cosmic rays. (IPCC 2001)
Though natural amounts of CO2 have varied from 180 to 300 parts per million (ppm), today's CO2 levels are around 380 ppm. That's 25% more than the highest natural levels over the past 650,000 years. Increased CO2
levels have contributed to periods of higher average temperatures
throughout that long record. (Boden, Carbon Dioxide Information
As for previous Arctic warming, it is true that there were stretches
of warm periods over the Arctic earlier in the 20th century. The
limited records available for that time period indicate that the warmth
did not affect as many areas or persist from year to year as much as
the current warmth. But that episode, however warm it was, is not
relevant to the issue at hand. Why? For one, a brief regional trend
does not discount a longer global phenomenon.
We know that the planet has been warming over the past several
decades and Arctic ice has been melting persistently. And unlike the
earlier periods of Arctic warmth, there is no expectation that the
current upward trend in Arctic temperatures will reverse; the rising
concentrations of greenhouse gases will prevent that from happening.
MYTH: We can adapt to climate change — civilization has survived droughts and temperature shifts before.
FACT: Although humans as a whole have survived the vagaries
of drought, stretches of warmth and cold and more, entire societies
have collapsed from dramatic climatic shifts.
The current warming of our climate will bring major hardships and
economic dislocations — untold human suffering, especially for our
children and grandchildren. We are already seeing significant costs
from today's global warming which is caused by greenhouse gas
pollution. Climate has changed in the past and human societies have
survived, but today six billion people depend on interconnected
ecosystems and complex technological infrastructure.
What's more, unless we limit the amount of heat-trapping gases we
are putting into the atmosphere, we will face a warming trend unseen
since human civilization began 10,000 years ago. (IPCC 2001)
The consequences of continued warming at current rates are likely to
be dire. Many densely populated areas, such as low-lying coastal
regions, are highly vulnerable to climate shifts. A middle-of-the-range
projection is that the homes of 13 to 88 million people around the
world would be flooded by the sea each year in the 2080s. Poorer
countries and small island nations will have the hardest time adapting.
(McLean et al. 2001)
In what appears to be the first forced move resulting from climate
change, 100 residents of Tegua island in the Pacific Ocean were
evacuated by the government because rising sea levels were flooding
their island. Some 2,000 other islanders plan a similar move to escape
rising waters. In the United States, the village of Shishmaref in
Alaska, which has been inhabited for 400 years, is collapsing from
melting permafrost. Relocation plans are in the works.
Scarcity of water and food could lead to major conflicts with broad
ripple effects throughout the globe. Even if people find a way to
adapt, the wildlife and plants on which we depend may be unable to
adapt to rapid climate change. While the world itself will not end, the
world as we know it may disappear.
MYTH: Recent cold winters and cool summers don’t feel like global warming to me.
FACT: While different pockets of the country have
experienced some cold winters here and there, the overall trend is
Measurements show that over the last century the Earth’s climate has
warmed overall, in all seasons, and in most regions. Climate skeptics
mislead the public when they claim that the winter of 2003–2004 was the
coldest ever in the northeastern United States. That winter was only
the 33rd coldest in the region since records began in 1896.
Furthermore, a single year of cold weather in one region of the globe
is not an indication of a trend in the global climate, which refers to
a long-term average over the entire planet.
MYTH: Global warming can’t be happening because some glaciers and ice sheets are growing, not shrinking.
FACT: In most parts of the world, the retreat of glaciers
has been dramatic. The best available scientific data indicate that
Greenland's massive ice sheet is shrinking.
Between 1961 and 1997, the world’s glaciers lost 890 cubic miles of
ice. The consensus among scientists is that rising air temperatures are
the most important factor behind the retreat of glaciers on a global
scale over long time periods. Some glaciers in western Norway, Iceland
and New Zealand have been expanding during the past few decades. That
expansion is a result of regional increases in storm frequency and
snowfall rather than colder temperatures — not at all incompatible with
a global warming trend.
In Greenland, a NASA satellite that can measure the ice mass over
the whole continent has found that although there is variation from
month to month, over the longer term, the ice is disappearing. In fact,
there are worrisome signs that melting is accelerating: glaciers are
moving into the ocean twice as fast as a decade ago, and, over time,
more and more glaciers have started to accelerate. What is most
alarming is the prediction, based on model calculations and historical
evidence, that an approximately 5.4 degree Fahrenheit increase in local
Greenland temperatures will lead to irreversible meltdown and a
sea-level rise of over 20 feet. Since the Arctic is warming 2-3 times
faster than the global average, this tipping point is not far away.
The only study that has shown increasing ice mass in Greenland only
looked at the interior of the ice sheet, not at the edges where melting
occurs. This is actually in line with climate model predictions that
global warming would lead to a short-term accumulation of ice in the
cold interior due to heavier snowfall. (Similarly, scientists have
predicted that Antarctica overall will gain ice in the near future due
to heavier snowfall.) The scientists who published the study were
careful to point out that their results should not be used to conclude
that Greenland's ice mass as a whole is growing. In addition, their
data suggested that the accumulation of snow in the middle of the
continent is likely to decrease over time as global warming continues.
MYTH: Accurate weather predictions a few days in
advance are hard to come by. Why on earth should we have confidence in
climate projections decades from now?
FACT: Climate prediction is fundamentally different from weather prediction, just as climate is different from weather.
It is often more difficult to make an accurate weather forecast than
a climate prediction. The accuracy of weather forecasting is critically
dependent upon being able to exactly and comprehensively characterize
the present state of the global atmosphere. Climate prediction relies
on other, longer ranging factors. For instance, we might not know if it
will be below freezing on a specific December day in New England, but
we know from our understanding of the region's climate that the
temperatures during the month will generally be low. Similarly, climate
tells us that Seattle and London tend to be rainy, Florida and southern
California are usually warm, and the Southwest is often dry and hot.
Today’s climate models can now reproduce the observed global average
climates over the past century and beyond. Such findings have
reinforced scientist’s confidence in the capacity of models to produce
reliable projections of future climate. Current climate assessments
typically consider the results from a range of models and scenarios for
future heat-trapping emissions in order to identify the most likely
range for future climatic change.
MYTH: As the ozone hole shrinks, global warming will no longer be a problem.
FACT: Global warming and the ozone hole are two different problems.
The ozone hole is a thinning of the stratosphere's ozone layer,
which is roughly 9 to 31 miles above the earth's surface. The depletion
of the ozone is due to man-made chemicals like chlorofluorocarbons
(CFCs). A thinner ozone layer lets more harmful ultraviolet (UV)
radiation to reach the earth's surface.
Global warming, on the other hand, is the increase in the earth's average temperature due to the buildup of CO2 and other greenhouse gases in the atmosphere from human activities.
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