The biggest polluter in the world is the US, and there are many reasons why. These reasons include the use of oil and gas, the military, and land use and forestry. There are also many environmental and social issues that the US faces, and it's time to address them.

Land use and forestry

In the United States, the land sector accounts for 50 times the nation's total annual greenhouse gas emissions. Land is a major contributor to the country's economy, and changing its use can affect global climate change. However, land use is subject to local zoning rules, making it difficult to regulate nationally.

Forests store 28 times the amount of greenhouse gas emissions produced by the land sector. These forests, which cover one third of the earth's land area, are the world's largest carbon sinks. They also provide an important source of livelihoods for 1.6 billion people. Fortunately, the carbon stored in forests helps combat climate change.

Deforestation, or the permanent removal of trees, leads to an increase in carbon dioxide emissions. It is estimated that deforestation contributes to 25 percent of the world's greenhouse gas emissions.

Agricultural soils also contribute to atmospheric carbon emissions. These include crops for human consumption and livestock production. Crop burning releases methane and nitrous oxide. Livestock also produce methane through digestive processes.

Oil and gas companies

The oil and gas industry is a huge source of methane, a greenhouse gas around 80 times more potent than carbon dioxide. This is a major problem, because it has the potential to cause more global warming than carbon dioxide.

According to the EDF, the energy sector contributes roughly one-third of all industrial greenhouse gas emissions, a staggering 65 billion tons. In addition to methane, the fossil fuel industry also produces air toxics. These chemicals are known to have health impacts, including cancer and aggravated asthma.

A report from the Environmental Defense Fund found that the largest companies in the fossil fuel industry haven't been doing much to reduce their GHG emissions. Instead, they've been selling off their dirty assets to private firms, who don't have to report them to shareholders.

The study examined more than 3,000 deals in the past two years. It looked at financial data, data from industry trade groups, and metrics based on a survey of environmental experts.

US military

The US military is a huge contributor to climate change. This is mainly due to the fact that it is the biggest institutional consumer of petroleum and other hydrocarbons. However, the US government doesn't report how much it uses, and its contribution is not always well known.

Researchers at the Durham and Lancaster Universities commissioned a study to investigate the US military's impact on the environment. Their findings revealed that the military was one of the top five contributors to global warming.

One of the most significant factors in the US military's contribution to climate change is its large-scale use of jet fuel. Jet fuel burns at a higher altitude and releases two to four times more carbon than other forms of fuel.

Another factor is the US's extensive global network of trucks and cargo planes, which facilitates the supply chain of all manner of goods from bombs to humanitarian aid.

It is no secret that the US has been involved in a number of wars over the last half century. These operations have devastated populations and landscapes in the countries they have intervened in.

China

Despite its size, China remains the world's biggest polluter. That is largely because of its dependence on coal for energy. Its carbon emissions are higher than those of the US and the EU combined.

Since joining the World Trade Organization in 2001, China's emissions have risen exponentially. In 2011, China's greenhouse gas emissions rose almost three-fold, to more than 14 gigatonnes CO2-equivalent.

Almost half of China's annual CO2 emissions come from coal. The country also produces a large amount of cement. As it transitions to a low-carbon economy, China will need to make major changes in the way it consumes energy.

Although China has pledged to stop burning fossil fuels by 2030, it has not committed to curbing its emissions in the way that other countries have. Instead, its commitments are in the form of carbon intensity. This is the idea that the responsibility for emissions should be shared according to the economic benefit they provide.