Private sector anger over President Trump's decision to pull the US out of the Paris Agreement and scrap Obama-era climate policies continues to grow as nations prepare to gather in Germany next month for the latest round of UN climate talks.
As countries prepare their delegations for the climate talks in Bonn, the 'We Are Still In' coalition of businesses, states and cities confirmed its membership has doubled to 2,584 signatories.
The group was set up in the wake of President Trump's controversial decision to quit the Paris Agreement, in a bid to demonstrate that many parts of US society remained committed to the international accord's goals.
The organisation announced this week that a surge in new supporters, including a Republican Mayor, five counties and 213 churches, mean the campaign now represents $6.2tr of the US economy, nine states, more than 250 cities and 1,780 businesses and investors.
The news coincided with the announcement of plans for a parallel US pavilion at the Bonn Summit which will represent the climate positive message of the We Are Still In campaign and champion the efforts of its members.
"It's critical for the world to know that the US will continue to lead on climate change - and that we can fulfill our Paris commitments even without help from Washington," said Michael Bloomberg, UN Special Envoy for Cities and Climate Change and convenor of the We Are Still In campaign. "By pitching a big tent in Bonn, we are providing space for American mayors, governors and business leaders to collaborate with their counterparts around the world. In the US, progress on climate change has always been driven from the ground up, not the top down - and that's what we'll emphasise in Bonn."
The US will still send an official team of negotiators to Bonn despite its intention to officially withdraw from the Paris Agreement, which according to the treaty's rulebook cannot happen before November 2020.
The show of force in support of US climate action comes as a new report from the Government Accountability Office (GAO) - Congress' expenditure watchdog - calculated the total cost of climate damage over the past decade at $350bn.
The cost of climate impacts is expected to increase further over the coming decades, the GAO warned, rising to as much as $35bn a year by 2050 unless the world can avoid dangerous levels of warming.
The body criticised the federal government's lack of "strategic government-wide planning" to manage impending climate risk, including the economic impact on the US economy.
Under the leadership of President Trump the current White House administration has set about unravelling key planks of President Obama's climate policy legacy, including his flagship plan to get states to cut emissions from power stations dubbed the Clean Power Plan.
However, Trump's efforts have sparked numerous legal challenges and vociferous opposition from business and state leaders across the country.
The GAO urges the Trump administration to take the threat of climate change seriously and start planning for its costs, issuing a high-profile rebuke to the President. Key risks include preparing for increased incidence of wildfires and droughts, as well as decreased harvests, higher energy demand and more frequent water shortages. Just this month wildfires in Northern California destroyed at least 8,400 buildings and resulted in more than $1bn of losses.