What is Global Warming?
(taken from: (http://www.wecansolveit.org/)
Earth is naturally insulated by a delicate balance of heat-trapping (or "greenhouse") gases in the atmosphere.
When the sun shines on the Earth, some of that heat is absorbed, keeping Earth warm enough to support life.
The problem
is that over the last century, we humans have been releasing more and more carbon dioxide and other heat-trapping gases into
the atmosphere when we burn fuels and cut down forests. These additional gases have upset the natural balance of our atmosphere,
trapping more heat than is healthy for the Earth.
The result is human-caused global warming, which brings serious threats
from increased flooding to the spread of disease to the disruption of agriculture in many parts of the world.
Scientists
tell us that stopping global warming is urgent -- we have just a few years to turn around the growth of greenhouse gas emissions
in order to avoid the worst effects. The good news is that we can achieve these emissions reductions with effective national
policies and international treaties. We must insist that businesses and governments join individuals around the world to greatly
increase energy efficiency, widely adopt renewable energy, and commit to stopping climate change. Success is possible, but
we need your help.
Climate crisis
No human challenge is so potentially uniting as the climate crisis. Our human drive to invent and
build has led to extraordinary advances and great technological promise. It's also had grave, unintended consequences.
And unless we face the climate crisis with ingenuity, resolve, and a sense of urgency, much of the world as we know it will
begin to unravel before our eyes.
The warning signs are plain to see. The 10 warmest years on record have all occurred
since 1990. Mountain glaciers are fading on every continent and the sea ice is melting. The seas have begun a slow but menacing
rise.
What is global warming?
The science behind global warming is often portrayed as enormously complex, but some of
it is quite simple. It begins with a ray of light, shot through space from the staggering inferno of our sun. That sunbeam
delivers energy to earth, giving us light and warmth and life.
As some of this energy radiates back toward space as
heat, a portion is absorbed by a delicate balance of heat-trapping (or "greenhouse") gases in the atmosphere that
create an insulating layer. Without the temperature control of this greenhouse effect, the Earth's average surface temperature
would be 0°F (-18°C), a temperature so low that the Earth would be frozen and could not sustain human life as we know
it.
The most abundant of the greenhouse gases is water vapor. In addition, there are other powerful greenhouse gases
like carbon dioxide (CO2), methane, and nitrous oxide. Each of these is a natural part of the never-ending cycle of life,
death, and decomposition on Earth. But since the onset of the Industrial Revolution humans have been pumping out more and
more of these and other greenhouse gases. Scientists are clear: human activities are contributing to global warming by adding
large amounts of heat-trapping gases to the atmosphere. Our fossil fuel use is the main source of these gases. Every time
we drive a car, use electricity from coal-fired power plants, or heat our homes with oil or natural gas, we release carbon
dioxide and other heat-trapping gases into the air. The second most important addition of greenhouse gases to the atmosphere
is related to deforestation, mainly in the tropics, as well as other land-use changes.
The concentration of CO2 in
the atmosphere is now 380 parts-per-million (ppm), 100 ppm higher than at the beginning of the Industrial Revolution. But
we can look back even further. By drilling into the deepest glacial ice we can measure CO2 deep into time. And this ice library
shows more carbon dioxide in the atmosphere than at any time in last 650,000 years.
As a result of the build up of
gases, the temperature is beginning to rise. Adults today have already felt the average global temperature rise more than
a full degree Fahrenheit (0.8°C) during our lifetimes. We expect another degree F by 2020 due to past emissions. Based
on modeling by an international body of experts studying the climate crisis, the Intergovernmental Panel on Climate Change
(IPCC), the temperature could increase by more than 7°F (4°C) by the end of the century in the absence of meaningful
efforts to rein in global warming pollution.
What happens when the global temperature rises?
For a global system that is delicately balanced, the rise in temperatures
will pose serious threats:
- Rising sea levels, leading to more coastal erosion, flooding during storms, and permanent
inundation
- Increased drought and increased incidence of wildfires
- Severe stress on many forests, wetlands,
alpine regions, and other natural ecosystems
- Impacts on human health as mosquitoes and other disease-carrying insects
and rodents spread diseases over larger geographical regions
- Disruption of agriculture in some parts of the world
due to increased temperature, water stress, and sea-level rise in low-lying areas such as Bangladesh or the Mississippi River
delta
Other projected impacts include increased intensity of hurricanes; the long-term destabilization of the
Greenland and West Antarctic ice sheets, leading to much greater sea level rise; the acidification of the world's oceans;
and a vastly increased rate of species extinction. Wonders such as the Great Barrier Reef and the Amazon could collapse under
the weight of just a few more degrees. And hundreds of millions of people may be forced from their homelands as the climate
shifts, creating increased political and economic instability.
What are the economic costs of the climate crisis?
The projected economic costs of the climate crisis are extraordinary.
By mid-century, extreme weather alone could cost 0.5 - 1% of the global economic production. A seminal study led by a distinguished
British economist, Sir Nicholas Stern, suggests that under business-as-usual scenarios climate change could reduce overall
economic activity in the range of 5 to 20%-more likely on the high side of this range. Think Great Depression, or world war.
Can we solve it?
We can - and must - act urgently if we are to limit and eventually halt the impacts of global
warming on human communities and natural ecosystems. The greater the magnitude and rate of warming, the greater the chances
are for truly devastating - and potentially irreversible - changes in the Earth's climate system. Even by acting today
to reduce our emissions from cars, power plants, land use, and other sources, we will see some degree of continued warming
for a period of time because past emissions will stay in the atmosphere for decades or more. But, the window for effective
action is closing fast and responding to the climate crisis will take commitment and ingenuity. The actions we take in the
next several years will determine the kind of world our children and grandchildren will inherit.
How much will it cost to solve?
The IPCC has estimated that stabilizing the concentration of greenhouse gases in
the atmosphere at levels that will limit long-term temperature rise to a few degrees will slow the rate of global economic
growth by only about a tenth of a percent per year. Based on the expected growth rate of the global economy, that is about
equivalent to the world reaching the expected 2030 economic levels in 2031 in return for preventing the worst effects of the
climate crisis.
Fortunately, we have the tools we need to start on the path to a stable climate. Fuel-efficient vehicles
and higher efficiency appliances; advanced wind turbines, next-generation solar photovoltaics and other renewable energy technologies; proven strategies to protect threatened forests; communities making it easier for people to walk and bike. These are just
a few of the common sense solutions that will not only reduce global warming, but can save us money and create new business
opportunities.
What should I do to help?
We have lacked full global leadership and political will to implement these solutions
as if our future depended on it. But now we need to insist that businesses and governments all over the world join individuals
in taking the steps needed to get the job done. We need to help citizens everywhere understand how the choices they make in
their daily lives can make a real difference, and we need to provide incentives for all of us to make better choices.
The
climate forces we have set loose are great indeed. But the world we build as we move forward to meet this challenge will be
a sight to behold. This is our opportunity to come together to make a real difference.The time to act is now.
