Query: (Koch Industries) is among the worst in toxic air pollution in the entire United States ... and churns out more climate-changing greenhouse gases than oil giants Chevron, Shell and Valero.

Relevant passages:
Carbon tax <=SEP=> A carbon tax is a tax levied on the carbon content of fuels . It is a form of carbon pricing . Carbon is present in every hydrocarbon fuel ( coal , petroleum , and natural gas ) and converted to carbon dioxide and other products when combusted . In contrast , non-combustion energy sources -- wind , sunlight , geothermal , hydropower , and nuclear -- do not convert hydrocarbons to . is a heat-trapping `` greenhouse '' gas which represents a negative externality on the climate system ( see scientific opinion on global warming ) . Since GHG emissions caused by the combustion of fossil fuels are closely related to the carbon content of the respective fuels , a tax on these emissions can be levied by taxing the carbon content of fossil fuels at any point in the product cycle of the fuel .   Carbon tax offers social and economic benefits . It is a tax that increases revenue without significantly altering the economy while simultaneously promoting objectives of climate change policy . The objective of a carbon tax is to reduce the harmful and unfavorable levels of carbon dioxide emissions , thereby decelerating climate change and its negative effects on the environment and human health .   Carbon taxes offer a potentially cost-effective means of reducing greenhouse gas emissions . From an economic perspective , carbon taxes are a type of Pigovian tax . They help to address the problem of emitters of greenhouse gases not facing the full social cost of their actions . Carbon taxes can be a regressive tax , in that they may directly or indirectly affect low-income groups disproportionately . The regressive impact of carbon taxes could be addressed by using tax revenues to favour low-income groups .   A number of countries have implemented carbon taxes or energy taxes that are related to carbon content . Most environmentally related taxes with implications for greenhouse gas emissions in OECD countries are levied on energy products and motor vehicles , rather than on emissions directly .   Opposition to increased environmental regulation such as carbon taxes often centers on concerns that firms might relocate and/or people might lose their jobs . It has been argued , however , that carbon taxes are more efficient than direct regulation and may even lead to higher employment ( see footnotes ) . Many large users of carbon resources in electricity generation , such as the United States , Russia , and China , are resisting carbon taxation .

Air pollution <=SEP=> Air pollution occurs when harmful substances including particulates and biological molecules are introduced into Earth 's atmosphere . It may cause diseases , allergies or death in humans ; it may also cause harm to other living organisms such as animals and food crops , and may damage the natural or built environment . Human activity and natural processes can both generate air pollution .   Indoor air pollution and poor urban air quality are listed as two of the world 's worst toxic pollution problems in the 2008 Blacksmith Institute World 's Worst Polluted Places report . According to the 2014 WHO report , air pollution in 2012 caused the deaths of around 7 million people worldwide , an estimate roughly matched by the International Energy Agency .

Global warming <=SEP=> Global warming , also referred to as climate change , is the observed century-scale rise in the average temperature of the Earth 's climate system and its related effects . Multiple lines of scientific evidence show that the climate system is warming . Many of the observed changes since the 1950s are unprecedented in the instrumental temperature record which extends back to the mid 19th century , and in paleoclimate proxy records over thousands of years .   In 2013 , the Intergovernmental Panel on Climate Change ( IPCC ) Fifth Assessment Report concluded that `` It is extremely likely that human influence has been the dominant cause of the observed warming since the mid-20th century . '' The largest human influence has been emission of greenhouse gases such as carbon dioxide , methane and nitrous oxide . Climate model projections summarized in the report indicated that during the 21st century the global surface temperature is likely to rise a further 0.3 to for their lowest emissions scenario and 2.6 to for the highest emissions scenario . These findings have been recognized by the national science academies of the major industrialized nations and are not disputed by any scientific body of national or international standing .   Future climate change and associated impacts will differ from region to region around the globe . Anticipated effects include warming global temperature , rising sea levels , changing precipitation , and expansion of deserts in the subtropics . Warming is expected to be greater over land than over the oceans and greatest in the Arctic , with the continuing retreat of glaciers , permafrost and sea ice . Other likely changes include more frequent extreme weather events including heat waves , droughts , heavy rainfall with floods and heavy snowfall ; ocean acidification ; and species extinctions due to shifting temperature regimes . Effects significant to humans include the threat to food security from decreasing crop yields and the abandonment of populated areas due to rising sea levels . Because the climate system has a large `` inertia '' and greenhouse gases will stay in the atmosphere for a long time , many of these effects will not only exist for decades or centuries , but will persist for tens of thousands of years .   Possible societal responses to global warming include mitigation by emissions reduction , adaptation to its effects , building systems resilient to its effects , and possible future climate engineering . Most countries are parties to the United Nations Framework Convention on Climate Change ( UNFCCC ) ,  whose ultimate objective is to prevent dangerous anthropogenic climate change . Parties to the UNFCCC have agreed that deep cuts in emissions are required and that global warming should be limited to well below 2.0 C-change relative to pre-industrial levels , with efforts made to limit warming to 1.5 C-change .   Public reactions to global warming and concern about its effects are also increasing . A global 2015 Pew Research Center report showed a median of 54 % consider it `` a very serious problem '' . There are significant regional differences , with Americans and Chinese ( whose economies are responsible for the greatest annual CO2 emissions ) among the least concerned .

Koch Industries <=SEP=> Koch Industries , Inc. . -LSB- ˈkoʊk -RSB- is an American multinational corporation based in Wichita , Kansas , United States , with subsidiaries involved in manufacturing , trading , and investments . It was founded as Wood River Oil and Refining Company in 1940 , and later as Rock Island Oil & Refining Company .   Koch also owns Invista , Georgia-Pacific , Molex , Flint Hills Resources , Koch Pipeline , Koch Fertilizer , Koch Minerals , Matador Cattle Company and recently Guardian Industries . Koch companies are involved in industries such as the manufacturing , refining , and distribution of petroleum , chemicals , energy , fiber , intermediates and polymers , minerals , fertilizers , pulp and paper , chemical technology equipment , ranching , finance , commodities trading , and other ventures and investments . The firm employs about 60,000 people in the United States and another 40,000 in 59 other countries .   In 2013 -- 2015 , Forbes listed it as the second largest privately held company in the United States ( after Cargill ) , with an annual revenue of $ 115 billion , down from the largest in 2006 . If Koch Industries were a public company in 2013 , it would have ranked 17 in the Fortune 500 .   Fred C. Koch , after whom Koch Industries , Inc. is named , co-founded the company in 1940 and developed an innovative crude oil refining process . His sons , Charles Koch , chairman of the board and chief executive officer , and David Koch , executive vice president , are principal owners of the company after they bought out their brothers , Frederick and William `` Bill '' Koch , for $ 1.1 billion in 1983 . Charles and David Koch each own 42 % of Koch Industries . Charles has stated that the company would go public `` over my dead body '' .

Valero Energy <=SEP=> Valero Energy Corporation is a Fortune 500 international manufacturer and marketer of transportation fuels , other petrochemical products , and power . It is headquartered in San Antonio , Texas , United States . The company owns and operates 16 refineries throughout the United States , Canada , United Kingdom , and the Caribbean with a combined throughput capacity of approximately 3 Moilbbl per day , 11 ethanol plants with a combined production capacity of 1.2 e9USgal per year , and a 50-megawatt wind farm . Before the 2013 spinoff of CST Brands , Valero was one of the United States ' largest retail operators with approximately 6,800 retail and branded wholesale outlets in the United States , Canada , United Kingdom , and the Caribbean under the Valero , Diamond Shamrock , Shamrock , Ultramar , Beacon , and Texaco brands .