Query: “climate economists see a positive externality, not a negative one, from the human influence on climate.

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 .

Highway <=SEP=> A highway is any public road or other public way on land . It is used for major roads , but also includes other public roads and public tracks : It is not an equivalent term to controlled-access highway , or a translation for autobahn , autoroute , etc. .   In North American and Australian English , major roads such as controlled-access highways or arterial roads are often state highways ( Canada : provincial highways ) . Other roads may be designated `` county highways '' in the US and Ontario . These classifications refer to the level of government ( state , provincial , county ) that maintains the roadway .   In British English , `` highway '' is primarily a legal term . Everyday use normally implies roads , while the legal use covers any route or path with a public right of access , including footpaths etc. .   The term has led to several related derived terms , including highway system , highway code , highway patrol and highwayman .   The term highway exists in distinction to `` waterway '' .

Tax <=SEP=> A tax ( from the Latin en : taxo #Latin ) is a financial charge or other levy imposed upon a taxpayer ( an individual or legal entity ) by a state or the functional equivalent of a state to fund various public expenditures . A failure to pay , or evasion of or resistance to taxation , is usually punishable by law . Taxes consist of direct or indirect taxes and may be paid in money or as its labour equivalent . Most countries have a tax system in place to pay for public/common/agreed national needs and government functions : some levy a flat percentage rate of taxation on personal annual income , some on a scale based on annual income amounts , and some countries impose almost no taxation at all , or a very low tax rate for a certain area of taxation . Some countries charge a tax both on corporate income and dividends ; this is often referred to as double taxation as the individual shareholder ( s ) receiving this payment from the company will also be levied some tax on that personal income .

Externality <=SEP=> In economics , an externality is the cost or benefit that affects a party who did not choose to incur that cost or benefit . Economists often urge governments to adopt policies that `` internalize '' an externality , so that costs and benefits will affect mainly parties who choose to incur them .   For example , manufacturing activities that cause air pollution impose health and clean-up costs on the whole society , whereas the neighbors of an individual who chooses to fire-proof his home may benefit from a reduced risk of a fire spreading to their own houses . If external costs exist , such as pollution , the producer may choose to produce more of the product than would be produced if the producer were required to pay all associated environmental costs . Because responsibility or consequence for self-directed action lies partly outside the self , an element of externalization is involved . If there are external benefits , such as in public safety , less of the good may be produced than would be the case if the producer were to receive payment for the external benefits to others . For the purpose of these statements , overall cost and benefit to society is defined as the sum of the imputed monetary value of benefits and costs to all parties involved . Thus , unregulated markets in goods or services with significant externalities generate prices that do not reflect the full social cost or benefit of their transactions ; such markets are therefore inefficient .