Why is co2 emissions a concern

Greenhouse gases, such as carbon dioxide, methane, nitrous oxide, and certain synthetic chemicals, trap some of the Earth's outgoing energy, thus retaining heat in the atmosphere. This heat trapping causes changes in the radiative balance of the Earth—the balance between energy received from the sun and emitted from Earth—that alter climate and weather patterns at global and regional scales. Multiple lines of evidence confirm that human activities are the primary cause of the global warming of the past 50 years.

However, beginning in the late s, the net global effect of human activities has been a continual increase in greenhouse gas concentrations. This change in concentrations causes warming and is affecting various aspects of climate, including surface air and ocean temperatures, precipitation, and sea levels. Human health, agriculture, water resources, forests, wildlife, and coastal areas are all vulnerable to climate change.

Many greenhouse gases are extremely long-lived in the atmosphere, with some remaining airborne for tens to hundreds of years after being released. These long-lived greenhouse gases become globally mixed in the atmosphere and their concentrations reflect past and recent contributions from emissions sources worldwide. Others, like tropospheric ozone, have a relatively short lifetime in the atmosphere.

In addition to greenhouse gases, other related factors, including other radiatively important substances and albedo, can alter the Earth's climate. Although this ROE question does not address radiatively important substances or albedo, both factors are important to understanding the planet's energy balance and the ways human activities may affect that balance. Some greenhouse gases are emitted exclusively from human activities e.

Others occur naturally but are found at elevated levels due to human inputs e. Anthropogenic sources result from energy-related activities e. Major greenhouse gases include carbon dioxide, methane, nitrous oxide, and various synthetic chemicals.

For example, it would take thousands of molecules of carbon dioxide to equal the warming effect of a single molecule of sulfur hexafluoride—the most potent greenhouse gas—in terms of ability to absorb heat, as evaluated by the Intergovernmental Panel on Climate Change IPCC. However, according to most respondents, confronting climate change will entail more than just policy changes; it will also require significant changes in how people live.

Even in the U. In most countries, publics tend to believe that much of the burden for dealing with climate change should be shouldered by wealthier countries. Still, despite considerable agreement on many climate issues, there are also important differences between regions and countries, and often, within nations. Concerns about climate change are especially common in Latin America and sub-Saharan Africa.

However, they are less prevalent in China and the U. Overall, people in countries with high levels of carbon dioxide CO2 emissions per capita tend to express less anxiety about climate change than those in nations with lower per-capita emissions. In a number of societies, views about climate change divide sharply along partisan lines. This is especially true in the U. For more on U. But the U.

In other economically advanced nations, such as Australia, Canada, Germany and the UK, those on the political left are significantly more likely than those on the right to view climate change as a major threat. These are among the key findings from a new Pew Research Center survey, conducted in 40 nations among 45, respondents from March 25 to May 27, People around the world are concerned about a variety of possible consequences of climate change, but drought tops the list. Survey respondents were presented with four potential effects of global warming, and were asked which one most concerns them: droughts or water shortages; severe weather, such as floods or intense storms; long periods of unusually hot weather; or rising sea levels.

Drought is the most common response or tied for the most common response in 31 countries, including the U. Many are worried about other consequences as well.

Methane from coal mines can also be captured and used for energy. Methane from manure management practices can be reduced and captured by altering manure management strategies.

Additionally, modifications to animal feeding practices may reduce emissions from enteric fermentation. Because CH 4 emissions from landfill gas are a major source of CH 4 emissions in the United States, emission controls that capture landfill CH 4 are an effective reduction strategy. Solomon, D. Qin, M. Manning, Z. Chen, M. Marquis, K. Averyt, M. Tignor and H. Miller eds. Cambridge University Press. Cambridge, United Kingdom pp.

In , nitrous oxide N 2 O accounted for about 7 percent of all U. Human activities such as agriculture, fuel combustion, wastewater management, and industrial processes are increasing the amount of N 2 O in the atmosphere.

Nitrous oxide is also naturally present in the atmosphere as part of the Earth's nitrogen cycle, and has a variety of natural sources. Nitrous oxide molecules stay in the atmosphere for an average of years before being removed by a sink or destroyed through chemical reactions.

The impact of 1 pound of N 2 O on warming the atmosphere is almost times that of 1 pound of carbon dioxide. Nitrous oxide emissions occur naturally through many sources associated with the nitrogen cycle, which is the natural circulation of nitrogen among the atmosphere, plants, animals, and microorganisms that live in soil and water. Nitrogen takes on a variety of chemical forms throughout the nitrogen cycle, including N 2 O. Natural emissions of N 2 O are mainly from bacteria breaking down nitrogen in soils and the oceans.

Nitrous oxide is removed from the atmosphere when it is absorbed by certain types of bacteria or destroyed by ultraviolet radiation or chemical reactions. To find out more about the sources of N 2 O and its role in warming the atmosphere, visit the Climate Change Indicators page. Nitrous oxide emissions in the United States have remained relatively flat between and Nitrous oxide emissions from mobile combustion decreased by 60 percent from to as a result of emission control standards for on-road vehicles.

Nitrous oxide emissions from agricultural soils have varied during this period and were about 9 percent higher in than in , primarily driven by increasing use of nitrogen fertilizers. The application of nitrogen fertilizers accounts for the majority of N 2 O emissions in the United States.

Emissions can be reduced by reducing nitrogen-based fertilizer applications and applying these fertilizers more efficiently, 3 as well as modifying a farm's manure management practices. Additionally, the introduction of pollution control technologies e. Production of adipic acid results in N 2 O emissions that can be reduced through technological upgrades.

Greenhouse Gas Mitigation Potential in U. Forestry and Agriculture. Unlike many other greenhouse gases, fluorinated gases have no natural sources and only come from human-related activities. They are emitted through their use as substitutes for ozone-depleting substances e. Many fluorinated gases have very high global warming potentials GWPs relative to other greenhouse gases, so small atmospheric concentrations can have disproportionately large effects on global temperatures.

They can also have long atmospheric lifetimes—in some cases, lasting thousands of years. Like other long-lived greenhouse gases, most fluorinated gases are well-mixed in the atmosphere, spreading around the world after they are emitted.

Many fluorinated gases are removed from the atmosphere only when they are destroyed by sunlight in the far upper atmosphere. In general, fluorinated gases are the most potent and longest lasting type of greenhouse gases emitted by human activities.

The largest sources of fluorinated gas emissions are described below. To find out more about the role of fluorinated gases in warming the atmosphere and their sources, visit the Fluorinated Greenhouse Gas Emissions page.

Overall, fluorinated gas emissions in the United States have increased by about 86 percent between and This increase has been driven by a percent increase in emissions of hydrofluorocarbons HFCs since , as they have been widely used as a substitute for ozone-depleting substances.

Emissions of perfluorocarbons PFCs and sulfur hexafluoride SF 6 have actually declined during this time due to emission reduction efforts in the aluminum production industry PFCs and the electricity transmission and distribution industry SF 6.

Because most fluorinated gases have a very long atmospheric lifetime, it will take many years to see a noticeable decline in current concentrations.