Wow, you really have to question your motivations when you're defending Exxon's climate change contribution. But OK, I'll play that game.

The IPCC was the source for the OpenSecrets statement (as they said in the quote). They just consolidated the information. Feel free to read the IPCC Report yourself.

Or The Guardian: https://www.theguardian.com/sustainable-business/2017/jul/10...

(Table shows ExxonMobile at 1.98%)

Or Statistica: https://www.statista.com/statistics/531354/greenhouse-gas-em...

Or Sustainability Now: http://sustainabilitynow.com/Docs/exxons_climate_footprint.p...

> The contribution of emissions from ExxonMobil to total carbon dioxide concentrations above pre-industrial levels in 2002 was 4.8 to 5.5%. This percentage contribution from ExxonMobil has steadily increased, rising from 0% in 1882, to 2.5 to 2.8% in 1960 and then almost doubling in the last forty years to 4.8 to 5.5% in 2002. The contribution of methane emissions is smaller, peaking at 1.6% of total global concentrations above pre-industrial levels, in 2002.