Two of Australia's Big Four banks appear to have discovered this week that glossy sustainability reports and fine sounding media releases on climate change initiatives might finally have a real price tag attached. And that price could be the cutting of ties with lobby groups such as the Business Council of Australia.Credit for making this happen has been claimed by the Australasian Centre for Corporate Responsibility, which has been targeting Australia's largest listed companies ahead of the forthcoming AGM season.The ACCR has been lodging resolutions to force big companies to explain why they are supporting industry lobby groups which advocate policies that conflict with their own stated positions - notably on climate change. First up was Westpac, which earlier this week backed down and agreed to review the Business Council of Australia's advocacy on climate issues, in response to a resolution the ACCR filed with the bank. The ACCR pointed out that Westpac has agreed, as part of its annual reporting, to set out principles for engagement with industry associations, and will commence a review of key industry association memberships, with a specific focus on lobbying and advocacy related to climate change. "As a result of Westpac's decision, we have withdrawn our resolution and will continue scrutinising all climate lobbying being done by industry associations in Australia including the BCA," the ACCR said in a media statement yesterday.And pre-empting the ACCR's lobbying, National Australia Bank yesterday became the first ASX 100 company to openly embrace the science of climate change and the need to limit global warming to 1.5 degrees Celsius above pre-industrial levels."In addition to supporting our customers through the low-carbon transition, we commit to working actively with our stakeholders - including the industry associations of which NAB is a member - to share our knowledge and data, and advocate for policy and actions that will limit global warming to less than two degrees," NAB said in a media statement last night."We are also committed to ensuring that our industry associations advocate for policy aligned with this goal. To this end, we will continue to review the advocacy activities of those industry associations, and commit to relevant disclosure to shareholders. "Where we identify a material misalignment, we will take this into consideration when deciding whether to renew our membership."NAB and Westpac are both vulnerable to this type of reverse lobbying by interest groups as they are among the largest and most vocal backers of alternative energy projects in Australia.How the remaining listed financial services companies, still aware of the shadow cast over the sector by the ongoing royal commission into misconduct in the banking, superannuation and financial services industry, deal with similar tactics from the ACCR ahead of their own AGMs remains to be seen.