A methodical review of the world's dominant fossil fuel producers has documented their poor performance—in some cases, egregious failure— in taking responsibility for their emissions of greenhouse gases and moving effectively to confront climate change.

"None of them has made a clean break from disinformation on climate science and policy," said a study by the Union of Concerned Scientists, published by four of its senior climate experts last week.

"None of the eight companies has laid out a company-wide pathway or plan to align its business model with the Paris Climate Agreement."

The study looked at BP, Chevron, Conoco Phillips, ExxonMobil, and Shell, the five largest investor-owned oil companies in cumulative emissions; as well as Arch Coal, CONSOL Energy and Peabody, which are the three leading coal companies by the same measure.

Exxon and the coal companies come out at the bottom of the responsibility rankings. Exxon and Chevron were called egregious for failing to renounce climate science denial, and the coal companies for failing to adjust to the low-carbon requirements of the new Paris agreement, which aims at reaching zero net emissions of carbon dioxide late in this century.

Only BP and Shell avoided low scores for the "accuracy and consistency of public statements on climate science and the consequent need for swift and deep reductions in emissions from the burning of fossil fuels."

UCS, a science advocacy group that has long campaigned for corporations to behave proactively on climate, argues that the eight companies bear special corporate responsibility for climate change, because they have accounted for 15 percent of global greenhouse gas emissions since the Industrial Revolution.

UCS called on the companies to renounce disinformation on climate science and policy; plan their corporate strategies around the march to a carbon-free world in as short a time as possible; support fair and effective climate policies in keeping with the new Paris agreement; and fully disclose climate risks to investors and the public.

The group has pushed hard for state and federal attorneys general and financial regulators to hold Exxon and other fossil fuel companies accountable for their climate policies. In particular, UCS has documented and criticized corporate support for groups that push views contrary to the scientific consensus on climate change.

This study goes beyond a generic, impressionistic complaint about the words and deeds of the fossil fuel industry. The science group fully explains its analysis, and its point-based ranking system includes many factors that make up each company's report card.

The UCS grades on a tough curve, and even the better performers earn only mediocre ratings. The worst, including Exxon and Peabody, come in for stern rebukes. (Both companies have been investigated by Eric Schneiderman, the attorney general of New York; Peabody reached a settlement a year ago, as his probe of Exxon was being disclosed.)

In painstaking fashion, using 30 separate metrics grouped into four main themes, the UCS scorecard ranks the companies' records in comparison to each other.

In some cases, the criteria are subjective, as in docking points for belonging to trade association or policy groups that take positions out of step with mainstream science or oppose particular climate policies. The UCS cited the companies' affiliations with the American Coalition for Clean Coal Electricity, the American Legislative Exchange Council, the American Petroleum Institute, the National Association of Manufacturers, the National Mining Association, the U.S. Chamber of Commerce, and the Western States Petroleum Association as markers against corporate climate accountability.

The UCS also objected to companies that oppose new federal regulations on carbon pollution from power plants, methane emissions from oil and gas fields—or ideas like a carbon price.

Companies were also marked down if they did not expressly endorse the Paris agreement, which is about to enter into force and which calls for moving rapidly to make steep cuts in carbon emissions. Similarly, if the companies did not put forth plans for moving to a low-carbon energy economy in line with the Paris targets, that drew a bad mark.

One appendix alone provides 47 pages of detailed analysis of each company's commitment to a low-carbon world—including page after page of material quoting each company's justifications of its approach.

For each of the eight companies reviewed, the report includes a separate scorecard. In Exxon's case, this runs seven pages and addresses in detail several aspects of the company's climate stance, such as its professed support for a tax on carbon, and its involvement with the American Legislative Exchange Council, which opposes such a tax.

On the question of a carbon tax, UCS rated Exxon "fair." It noted that Exxon has declared that it supports a revenue-neutral carbon tax—in other words, one that pays back all revenues in the form of individual or corporate tax cuts. But it also pointed out that Exxon's own External Citizenship Advisory Panel has asked for more specific details about this and other climate policies.

On the Clean Power Plan, major emissions regulations that industry and fossil fuel-friendly states have challenged in court, Exxon was rated "poor" because it funded the Pacific Legal Foundation, one of the plaintiffs opposing the rules.