There is no single solution to global warming, which is primarily a problem of too much heat-trapping carbon dioxide (CO2), methane and nitrous oxide in the atmosphere. The technologies and approaches outlined below are all needed to bring down the emissions of these gases by at least 80 percent by mid-century. To see how they are best deployed in each region of the world, use the menu at left.
1. Boosting energy efficiency: The energy used to power, heat, and
cool our homes, businesses, and industries is the single largest contributor to
global warming. Energy efficiency technologies allow us to use less energy to
get the same or higher level of production, service, and comfort. This approach
has vast potential to save both energy and money, and can be deployed quickly.
2. Greening transportation: The transportation
sector's emissions have increased at a faster rate than any other energy-using
sector over the past decade. A variety of solutions are at hand, including
improving efficiency (miles per gallon) in all modes of transport, switching to
low-carbon fuels, and reducing vehicle miles traveled through smart growth and
more efficient mass transportation systems.
3. Revving up renewables: Renewable energy sources such as solar, wind, geothermal
and bioenergy are available around the world. Multiple studies have shown that
renewable energy has the technical potential to meet the vast majority of our
energy needs. Renewable technologies can be deployed quickly, are increasingly
cost-effective, and create jobs while reducing pollution.
4 .Phasing out fossil fuel electricity: Dramatically
reducing our use of fossil fuels especially carbon-intensive coal is essential
to tackle climate change. There are many ways to begin this process. Key action
steps include: not building any new coal-burning power plants, initiating a
phased shutdown of coal plants starting with the oldest and dirtiest, and
capturing and storing carbon emissions from power plants. While it may sound
like science fiction, the technology exists to store carbon emissions
underground. The technology has not been deployed on a large scale or proven to
be safe and permanent, but it has been demonstrated in other contexts such as
oil and natural gas recovery. Demonstration projects to test the viability and
costs of this technology for power plant emissions are worth pursuing.
5. Managing forests and agriculture: Taken together, tropical deforestation
and emissions from agriculture represent nearly 30 percent of the world's
heat-trapping emissions. We can fight global warming by reducing emissions from
deforestation and forest degradation and by making our food production
practices more sustainable.
6. Exploring nuclear: Because nuclear power results in few global warming
emissions, an increased share of nuclear power in the energy mix could help
reduce global warming but nuclear technology poses serious threats to our
security and, as the accident at the Fukushima Diaichi plant in Japan
illustrates to our health and the environment as well. The question remains:
can the safety, proliferation, waste disposal, and cost barriers of nuclear
power be overcome?
7. Developing and deploying new low-carbon and
zero-carbon technologies: Research into and development of the next generation of
low-carbon technologies will be critical to deep mid-century reductions in
global emissions. Current research on battery technology, new materials for
solar cells, harnessing energy from novel sources like bacteria and algae, and
other innovative areas could provide important breakthroughs.
The ozone layer is a layer in Earth's atmosphere which contains relatively high
concentrations of ozone (O3). This layer absorbs 97-99% of the sun's high
frequency ultraviolet light, which is potentially damaging to life on earth.
Over 90% of ozone in earth's atmosphere is
present here "Relatively high" means a few parts per million much
higher than the concentrations in the lower atmosphere but still small compared
to the main components of the atmosphere.
It is mainly located in the lower portion of
the stratosphere from approximately 15 km to 35 km above Earth's surface,
though the thickness varies seasonally and geographically.
A thinning ozone layer leads to a number of
serious health risks for humans. It causes greater incidences of skin cancer
and cataract of the eye, with children being particularly vulnerable. There are
also serious impacts for biodiversity. Increased UV-B rays reduce levels of
plankton in the oceans and subsequently diminish fish stocks. It can also have
adverse effects on plant growth, thus reducing agricultural productivity.
Another negative effect is the reduced lifespan of certain materials.