For a decade now – since Ken Saro-Wiwa’s death and the Brent Spar fiasco – Shell has done its utmost to portray itself as a green oil company.

It hasn’t quite gone to the lengths of its rival BP and completely rebranded its logo, but it has spent millions of dollars trying to change perceptions that it is not a villain but a good corporate citizen.

But so often the company’s credentials come up short.  Take reporting of its carbon emissions. Its adverts might show a net trying to catch CO2, but the company itself seems reluctant to disclose how much CO2 it is catching.

The Financial Times has reported that “Royal Dutch Shell’s disclosure of its carbon emissions lags behind its closest rivals and falls well short of best practice, a study by an industry consultant has said.”

According to the energy consultant, PFC Energy, Shell is rated bottom out of six multi-national oil companies surveyed on the level of detail, frequency and coherency of their emissions disclosures. In contrast, Shell’s rival, BP, was ranked highest. Even ExxonMobil, traditionally seen as a oil industry dinosaur on climate change, was rated above Shell.

PFC bases its rankings on publicly available data from corporate sustainability reports, annual reports and corporate websites. It scored Shell 1.15 out of 5 on its carbon disclosures, whereas BP got 3.05 and Exxon 2.76.

PFC said Shell’s performance on disclosure raised questions about its internal organisation – five years after Shell was hit by a scandal when it was revealed that oil and gas reserves had been overstated. “The possibility exists that the upheaval Shell has experienced over the last decade – the reserves writedown and massive corporate and business reorganisations – has made it difficult for the group to quantify its emissions thoroughly,” PFC said.

Shell argues though that it has been rated more highly on a broader set of criteria by the Carbon Disclosure Project. The company claims that “It is still early days on GHG [greenhouse gas] reporting”.

I wonder if one of the reasons that Shell is worried about greenhouse gas reporting is that fact that it is still flaring widely in Nigeria – a huge contribution to climate change.