What is it/worst situations/efforts to prevent it:-Global Warming

Global Warming is the increase of Earth's average surface temperature due to effect of greenhouse gases, such as carbon dioxide emissions from burning fossil fuels or from deforestation, which trap heat that would otherwise escape from Earth. New York City (The bleak image is brought home when emissions over the last few decades are plotted against projections for the future. Models predict how much the world will warm depending on how much we emit in future. Scientists typically look at four different possible futures, ranging from an uber-green society to a worst-case scenario, in which no action is taken to combat global warming. Le Qur and her colleagues show how today's emissions are near-perfectly in line with the worst-case scenario. This means that, according to scientists' best estimates, the world will be as much as 5.4 C warmer in 2100 than it was before the industrial revolution.)

LIMIT GLOBAL WARMING POLLUTION

Raise your voice. Congress needs to enact new laws that cap carbon emissions and require polluters pay for the global warming gases that they produce. Send a message to your elected officials, letting them know that you will hold them accountable for what they do -- or fail to do -- about global warming. Take action here.

GREEN JOBS AND CLEAN ENERGY

Choose renewable energy. Pick a Green-e-certified energy supplier that generates at least half of its power from wind, solar energy and other clean sources. If you don't have that option, look at your current electricity bill to see if you are able to support renewable energy in another way. For details, see NRDC's guide to buying clean energy.

Offset your carbon footprint. You can make up for your remaining carbon output by purchasing carbon offsets. Offsets represent clean power that you can add to the nation's energy grid in place of power from fossil fuels. Not all offset companies are alike. See our guide to carbon offsets for tips on how to choose an offset supplier.

DRIVE SMARTER CARS

Choose an efficient vehicle: High-mileage cars such as hybrids and plug-in hybrids use less gas and save money. Over its lifetime, a 40-mpg car will save roughly $3,000 in fuel costs compared with a 20-mpg car. Compare fuel economy performance before you buy.

Drive smart. If all Americans kept their tires properly inflated, gasoline use nationwide would come down 2 percent. A tune-up could boost your miles per gallon anywhere from 4 to 40 percent, and a new air filter could get you 10 percent more miles per gallon. Learn more about saving fuel and money through proper car maintenance.

GREEN HOMES AND BUILDINGS

Weatherize your home or apartment. Heating and cooling consume about 40 percent of energy in the home. Sealing drafts and making sure that your home has adequate insulation are two easy ways to become more energy-efficient. Learn how to take advantage of federal tax credits for energy-efficient home improvements.

Buy energy-efficient appliances. Look for the Energy Star label, which identifies the most efficient appliances. Learn more about investing in energy-efficient products.

Replace your light bulbs with compact fluorescent bulbs. Compact fluorescent bulbs (CFLs) last 10 times longer than incandescent bulbs. What's more, CFLs lower your energy bills and keep a half-ton of carbon dioxide out of the air. Learn more on the benefits of switching to CFLs or LEDs.

BETTER COMMUNITIES AND TRANSPORTATION

Drive less. Choose alternatives to driving such as public transit, biking, walking and carpooling, and bundle your errands to make fewer trips. Choosing to live in a walkable "smart growth" community near a transportation hub will mean less time driving, less money spent on gas and less pollution in the air. Learn more about smart growth communities.Ozone Layer Depletion

Ozone layer depletion, is simply the wearing out (reduction) of the amount of ozone in the stratosphere. Unlike pollution, which has many types and causes, Ozone depletion has been pinned down to one major human activity. When CFCs and HCFCs reach the stratosphere, the ultraviolet radiation from the sun causes them to break apart and release chlorine atoms which react with ozone, starting chemical cycles of ozone destruction that deplete the ozone layer. One chlorine atom can break apart more than 100,000 ozone molecules. the 1950's, that ozone levels were relatively stable until the late 1970's. Observations of an Antarctic ozone "hole" and atmospheric records indicating seasonal declines in global ozone levels provide strong evidence that global ozone depletion is occurring.

Severe depletion over the Antarctic has been occurring since 1979 and a general downturn in global ozone levels has been observed since the early 1980's. The ozone hole over the Antarctic reached record proportions in the spring of 2000 at 28.3 million square kilometres and vertical profiles from stations near the South pole showed complete ozone destruction in the lower stratosphere. Ozone decreases of as much as 70% have been observed on a few days.

Severe ozone depletion was also measured over the Arctic. Lowest values over the Arctic occurred in 2000 north of Sweden, with about 60% depletion in some layers of the atmosphere. In addition to the Earth's poles, ozone depletion now affects almost all of North America, Europe, Russia, Australia, New Zealand, and a sizable part of South America. However, smaller decreases in stratospheric ozone have been observed in mid-latitude regions of the world. Limit private vehicle driving

A very easy way to control ozone depletion would be to limit or reduce the amount of driving as vehicular emissions eventually result in smog which is a culprit in the deterioration of the ozone layer. Car pooling, taking public transport, walking, using a bicycle would limit the usage of individual transportation. It would be a great option to switch to cars/vehicles that have a hybrid or electric zero-emission engine.

Use eco-friendly household cleaning products

Usage of eco-friendly and natural cleaning products for household chores is a great way to prevent ozone depletion. This is because many of these cleaning agents contain toxic chemicals that interfere with the ozone layer. A lot of supermarkets and health stores sell cleaning products that are toxic-free and made out of natural ingredients. Avoid using pesticides

Pesticides may be an easy solution for getting rid of weed, but are harmful for the ozone layer. The best solution for this would be to try using natural remedies, rather than heading out for pesticides. You can perhaps try to weed manually or mow your garden consistently so as to avoid weed-growth.

Developing stringent regulations for rocket launches

The world is progressing in scientific discoveries by leaps and bounds. A lot of rocket launches are happening the world over without consideration of the fact that it can damage the ozone layer if it is not regulated soon. A study shows that the harm caused by rocket launches would outpace the harm caused due to CFCs. At present, the global rocket launches do not contribute hugely to ozone layer depletion, but over the course of time, due to the advancement of the space industry, it will become a major contributor to ozone depletion. All types of rocket engines result in combustion by products that are ozone-destroying compounds that are expelled directly in the middle and upper stratosphere layer near the ozone layer.

Banning the use of dangerous nitrous oxide

Due to the worldwide alarm caused by a study in the late 70s about the alarming rate at which the ozone was being depleted, nations around the globe got together and formed the Montreal Protocol in the year 1989 with a strong aim to stop the usage of CFCs. However, the protocol did not include nitrous oxide which is the most fatal chemical that can destroy the ozone layer and is still in use. Governments across the world should take a strong stand for banning the use of this harmful compound to save the ozone layer. There has been considerable progress in finding non-ozone-depleting substitutes for ODS in the last few years. Substitutes for air-conditioning and refrigeration applications are now available, such as that HCFC-22 can be replaced by HFC-410A, CFC-12 can be replaced by HFC-134a. There are also emerging markets for "drop-in" replacement for HCFCs and halons.Acid Rain

Acid rain is a type of acid deposition, which can appear in many forms that causes harm to the environment (especially forest and lakes). Wet deposition is rain, sleet, snow, or fog that has become more acidic than normal. Dry deposition is another form of acid deposition, and this is when gases and dust particles become acidic. The main cause is the industrial burning of coal and other fossil fuels, the waste gases from which contain sulfur and nitrogen oxides, which combine with atmospheric water to form acids. China had its worst spell of acid rain in August 2006 with Beijing among the hardest hit. The CMA report said 19 of the 155 acid-rain monitoring stations across China recorded acid rain every rainy day last month. Beijing had 80 percent acid-rain days, the news service Xinhua reported. Rain traditionally slacks off from September on. China is the world's biggest sulfur dioxide polluter, with 25.49 million tons discharged in 2005, up 27 percent from 2000.

The Adirondack Park, located in upstate New York, suffered the worst damage in the nation from acid rain. Utility plant pollution from the highly industrial Midwest states of Ohio, Illinois, Indiana and Pennsylvania, is carried Northeast via wind patterns. As the winds rise over the Adirondack Mountains, the moisture they contain cools and condenses into clouds. The moisture, saturated with heavy amounts of nitric and sulfuric acid, precipitates onto the Adirondack Mountains, damaging the vegetation. Precipitation can be more than 200 times more acidic than natural rain, with a pH of 3.3 or less. Now, more than 500 lakes and ponds (out of 2,800) in the Adirondack Park are already too acidic to support the plants and aquatic wildlife that once existed in them. Clean up smokestacks and exhaust pipes

Almost all of the electricity that powers modern life comes from burning fossil fuels such as coal, natural gas, and oil. Acid deposition is caused by two pollutants that are released into the atmosphere when fossil fuels are burned: sulfur dioxide (SO2) and nitrogen oxides (NOx). Coal accounts for most U.S. SO2 emissions and a large portion of NOx emissions. Sulfur is present in coal as an impurity, and it reacts with air when the coal is burned to form SO2. In contrast, NOx is formed when any fossil fuel is burned.

There are several options for reducing SO2 emissions, including using coal containing less sulfur, washing the coal, and using devices called scrubbers to chemically remove the SO2 from the gases leaving the smokestack. Power plants can also switch fuelsfor example, burning natural gas creates much less SO2 than burning coal. Certain approaches will also have the additional benefit of reducing other pollutants such as mercury and carbon dioxide (CO2). Understanding these co-benefits has become important in seeking cost-effective air pollution reduction strategies. Finally, power plants can use technologies that do not burn fossil fuels. Each of these options, however, has its own costs and benefits; there is no single universal solution.

Similar to scrubbers on power plants, catalytic converters reduce NOx emissions from cars. These devices have been required for over 20 years in the United States, and it is important to keep them working properly. Recently, tailpipe restrictions were tightened to help curb NOx emissions. EPA also continues to make, changes to gasoline that allow it to burn cleaner. Use alternative energy sources

There are other sources of electricity besides fossil fuels. They include nuclear power, hydropower, wind energy, geothermal energy, and solar energy. Nuclear and hydropower are used most widely in the United States, while wind, solar, and geothermal energy have not yet been harnessed on a large enough scale to make them economically-feasible alternatives.

There are also alternative energies, such as natural gas, batteries, and fuel cells, available to power automobiles.

All sources of energy have environmental costs as well as benefits. Some types of energy are more expensive to produce than others, which means that not all Americans can afford all of them. Nuclear power, hydropower, and coal are the cheapest formsof energy today, but advancements in technologies and regulatory developments may change this in the future. All of these factors must be weighed when deciding which energy source to use today and which to invest in for tomorrow. Restore a damaged environment

Acid deposition penetrates deeply into the fabric of an ecosystem, changing the chemistry of the soil and streams and narrowingsometimes to nothingthe space where certain plants and animals can survive. Because there are so many changes, it takes many years for ecosystems to recover from acid deposition, even after emissions are reduced and the rain pH is restored to normal. For example, while visibility might improve within days, and small or episodic chemical changes in streams improve within months, chronically acidified lakes, streams, forests, and soils can take years to decades, or even centuries (in the case of soils) to heal.

However, there are some things that people can do to bring back lakes and streams more quickly. Limestone or lime (a naturally occurring basic compound) can be added to acidic lakes to cancel out the acidity. This process, called liming, has been used extensively in Norway and Sweden but is not used very often in the United States Liming tends to be expensive, has to be done repeatedly to keep the water from returning to its acidic condition, and is considered a short-term remedy in only specific areas, rather than an effort to reduce or prevent pollution. Furthermore, it does not solve the broader problems of changes in soil chemistry and forest health in the watershed, and it does nothing to address visibility reductions, materials damage, and risk to human health. However, liming does often permit fish to remain in a lake, allowing the native population to survive in place until emissions reductions reduce the amount of acid deposition in the area. Look to the future

As emissions from the largest known sources of acid depositionpower plants and automobilesare reduced, EPA scientists and their colleagues must assess the reductions to make sure they are achieving the results that Congress anticipated when it created the Acid Rain Program in 1990. If these assessments show that acid deposition is still harming the environment, Congress may begin to consider additional ways to reduce emissions that cause acid deposition. It may consider additional emission reductions from sources that have already been controlled, or methods to reduce emissions from other sources. Congress may also focus on energy efficiency and alternative energy. Implementation of cost-effective mechanisms to reduce emissions and their impact on the environment will continue to evolve. Take action as individuals

It may seem like there is not much that one individual can do to stop acid deposition. However, like many environmental problems, acid deposition is caused by the cumulative actions of millions of individual people. Therefore, each individual can also reduce their contribution to the problem and become part of the solution. Individuals can contribute directly by conserving energy, since energy production causes the largest portion of the acid deposition problem. For example, you can:

Turn off lights, computers, and other appliances when you're not using them.

Use energy-efficient appliances: lighting, air conditioners, heaters, refrigerators, washing machines, etc. For more information, see EPAs ENERGY STAR Program Exit EPA Disclaimer.

Only use electric appliances when you need them.

Keep your thermostat at 68F in the winter and 72F in the summer. You can turn it even lower in the winter and higher in the summer when you are away from home.

Insulate your home as best you can.

Carpool, use public transportation, or better yet, walk or bicycle whenever possible

Buy vehicles with low NOx emissions, and properly maintain your vehicle.

Be well informed.Haze

Haze is traditionally an atmospheric phenomenon where dust, smoke and other dry particles obscure the clarity of the sky. Haze reduces how far and how well you can see the view. The 2006 Southeast Asian haze event was caused by continued uncontrolled burning from "slash and burn" cultivation in Indonesia, and affected several countries in the Southeast Asian region and beyond, such as Malaysia, Singapore, southern Thailand, and as far as Saipan 2013 Singapore: The three-hour Pollutant Standards Index (PSI), which measures air quality, climbed steadily throughout yesterday, reaching a high of 155 by 10pm, crossing into the unhealthy range. The last time Singapore saw such bad smog was in 1997, when the PSI topped 226.

Laws must be changed and strengthened.The outgoing President of Indonesia has a chance to firmly establish his "green" legacy before it goes up in smoke. Legislation must be urgently passed to protect all forests and all peat, no matter how deep it is or whether it is in existing concessions or not. The government must also take other measure such as clearing the web of confusing contradictory policies across different sectors, and create a transparent and credible system mapping land use and ownership. Companies must end their role in peat and forest destruction. Companies operating in risky areas like Sumatra need to recognize there is a problem and then choose to be part of the solution. This starts with a commitment to No Deforestation, which means immediately stopping the bulldozers while implementing its commitment. Already there has been a wave of momentum: from household brands through to producers on the ground. Policies to curb activities that may lead to land and forest fires and control emissions from mobile and stationary sources, including the prohibition of open burning and the strict control of slash-and-bum practices during the dry period. Strategies to curb activities that may lead to land and forest fires and control emissions from mobile and stationary sources, including the following:

formulation of air quality management legislation to prohibit open burning;

strict enforcement of laws and legislation;

implementation of air quality monitoring and reporting regimes, and setting up surveillance on local sources of emissions, both mobile and stationary;

establishment of national task force/ committee to develop strategies and response plans to deal with fires and smoke haze; and

utilisation of information technology to provide haze-related information to relevant agencies to prevent and control spread of fire, and to enhance public awareness on the haze situation.

Guidelines and support services to discourage activities, which can lead to land and forest fires.

Operating procedures for the early mobilisation of resources to prevent the spread of fires.

Development of markets for the economic recovery and utilisation of biomass (e.g. briquette) and appropriate methods for the disposal of agricultural waste.Pollution

Pollution is the introduction of contaminants into the natural environment that cause adverse change. Pollution can take the form of chemical substances or energy, such as noise, heat or light. Pollutants, the components of pollution, can be either foreign substances/energies or naturally occurring contaminants. Pollution means any contamination of air, soil, water and environment. Why, even loud noise and sound is also a part of pollution. The Worlds Worst Polluted series of reports has effectively raised global awareness about the extent and the impacts of toxic pollution in low- and middle-income countries. Last year, we looked back to the original top ten list from 2007 and updated the list to name a new top ten worst polluted places. This year we look back to our 2009 report, 12 Cases of Cleanup and Success for inspiration and highlight the commitment and progress specific countries are making in turning the corner on toxic pollution. This years ten projectssuccess storiesshowcase how countries are saving lives, improving human health and restoring environments. These projects are the result of extraordinary perseverance, hard work and determined leadership by champions inside government agencies, civil society groups and individual communities. Clean Energy

Clean energy is renewable energy which doesn't deplete natural resources or cause environmental harm. Renewable energy includes bioenergy, wind, hydroelectricity, solar and geothermal energy.

Bioenergy is produced from living things such as trees and plants. Certain crops are grown, such as corn and soybeans and harvested to produce energy in the form of biofuel.

Wind turbines convert kinetic energy by moving air into mechanical energy, which is then converted into electricity. No emissions or solid wastes are produced during the production wind energy, but can often have the negative impact of noise pollution.

Hydroelectricity is electricity produced by the gravitational force of falling or flowing water. Many of the world's dams also serve as hydroelectric plants. This is currently the most widely used form of renewable energy.

Solar power is energy produced from the heat and light of the sun.

Geothermal energy is the naturally occurring thermal energy that is produced by the Earth's molten inner core. Electric Cars and Hybrids

Electric cars are powered exclusively by electricity instead of gasoline, which is stored in the car's rechargeable batteries. In the past, major automakers would not commit to producing this type of vehicle since the battery charges had very limited driving ranges before needing to be recharged. In addition, the recharging times were extremely long and production costs were very high. With new battery technology, electric cars are more cost effective, have an increased energy storage and require shorter recharging times. This means that automakers have finally embraced this technology.

Hybrid cars use a combination of electricity and gas. The car has an electric motor as well as an internal combustion engine. This allows the car to use less gas. Preventing Water Pollution

There are several things you can do to stop water pollution and they are very easy. Steps you can take to help prevent water pollution include:

Don't litter, especially in or near water sources

Organize a community cleanup event near a river or lake where you live

Use green household cleaners and laundry detergents

Use natural lawn fertilizers, such as manure instead of chemical fertilizers

Buy organic food that is produced without the use of chemical pesticides or fertilizers

Dispose of hazardous materials, such as paint, motor oil, antifreeze and lawn fertilizers responsibly, never down household drains or in the gutter

Preventing Soil Pollution

To help prevent top soil pollution, follow the same steps used to prevent water pollution, such as changing over to organic cleaners and detergents, and disposing of toxic chemicals and solvents responsibly. Other steps you can take to help stop land pollution include:

Recycle paper, plastics, aluminum cans and other materials to reduce garbage in landfills

Join a community effort to replant trees

Buy reusable cloth grocery bags to use instead of plastic bagsFlash Flood Flash floods are short-term events, occurring within 6 hours of the causative event (heavy rain, dam break, levee failure, rapid, snowmelt and ice jams) and often within 2 hours of the start of high intensity rainfall. A flash flood is a rapid flooding of geomorphic low-lying areas: washes, rivers, dry lakes and basins. It may be caused by heavy rain associated with a severe thunderstorm, hurricane, tropical storm, or meltwater from ice or snow flowing over ice sheets or snowfields. http://en.wikipedia.org/wiki/List_of_deadliest_floods Retaining walls

In some places, retaining walls levees, lakes, dams, reservoirs or retention ponds have been constructed to hold extra water during times of flooding.

Town planning

It is important that builders acquire permission before buildings are erected. This will ensure that that waterways are not blocked. Also drainage systems must be covered and kept free from objects that chock them. This way, water can quickly run through if it rains and minimize any chance of town flooding. Drainage systems should also be covered to prevent litter from getting into them.

Vegetation

Trees, shrubs and grass help protect the land from erosion by moving water. People in low-lying areas must be encouraged to use a lot of vegetation to help break the power of moving flood water and also help reduce erosion.

Education

In many developing countries, drainage systems are chocked with litter and people have little knowledge of the effects that can have during a rain. When it rains, waterways and culverts are blocked by massive chunks of litter and debris, and water finds its way into the streets and into peoples homes. Education is therefore very important, to inform and caution people on the dangers of floods, what causes floods, and what can be done to minimise its impact.

Detention basin

These are small reservoirs built and connected to waterways. They provide a temporary storage for floodwaters. This means in an event of flooding, water is drained into the basin first, giving people more time to evacuate. It can also reduce the magnitude of downstream flooding.Habitat Destruction (Flora & Fauna)

Habitat destruction is the process in which natural habitat is rendered functionally unable to support the species present. In this process, the organisms that previously used the site are displaced or destroyed, reducing biodiversity. Habitat destruction from human activity is the primary cause of risk for 83% of endangered plant species. The chief proximate causes of habitat destruction are:

Conversion of natural habitat for agricultural use including crops and grazing activity

Pollution, especially chemical herbicide and pesticide use, water pollution, air pollution and acid rain

Urban development and infrastructure, including roads, power plants, desert solar arrays, pipelines and transmission lines

Timber harvesting and slash-and-burn practices leading to deforestation

Introduction of alien species Help reduce pollution that can damage wildlife and habitat.

Before building on your property, learn about the natural habitat that may be impacted. There may be options to modify your project in order to better protect sensitive ecosystems on your land, and allow you to enjoy the wildlife that lives there.

Help to ensure the value of functioning natural systems is considered in land use decisions, and consider applying some of the principles of "Smart Growth" in planning. (See Ecosystem Valuation and Smart Growth in the More Information section.)

By using proactive shoreline and streamside development techniques, you may be able to simultaneously preserve habitat and reduce erosion and flood damage. For example, ensure buildings are set back an appropriate distance from the water body, limit the use of seawalls, and use native plants as a buffer along the shoreline.

Preserve existing wetland and salt marsh vegetation on your property, as it provides valuable habitat for birds, fish, amphibians and mammals. These areas also help to filter and store water and protect the shoreline from erosion and wave damage.

Plant native vegetation around your home and property. It provides habitat for native animals, limits the spread of invasive species, helps to prevent erosion, and usually requires less watering and maintenance (see natural gardening techniques)

When undertaking construction on your property, make sure sediment and pollutants do not run off into nearby streams and harbours.

Help to prevent the spread of invasive species in natural habitats.

Encourage the protection of key habitats through legislation, such as ecological reserves, parks, Marine Protected Areas and conservation covenants (see More Information). Keep in mind, however, such areas should also be linked with surrounding natural habitats, to avoid habitat fragmentation. Consider options to conserve wetlands and estuaries on your property. These provide valuable juvenile fish rearing habitat.

Learn about methods available for agricultural operators to reduce damage to streams and the marine environment.

Where possible, leave large woody debris, such as fallen trees, in streams. It helps to slow down the flow of water, and creates sheltered pools for fish.

Ensure that sediment from construction activities is contained to prevent it flowing into nearby streams and wetlands (see "regulations and guidelines for development around water" in More Information).

Increase and improve fish habitat, while controlling erosion and sedimentation, by maintaining and planting native vegetation along shores and stream banks.

Eelgrass beds are important habitat for many fish species; see that link, as well as tips for protecting marine vegetation.