Before the news of Donald Trump's decision to exit the Paris Climate agreement broke, we heard the opinions of several leading experts in climate science about what exactly it would mean if the US pulled out of the global deal.
Here's what they had to say.
This article was originally published on 29 May 2017.
We could soon know if the United States of America is pulling out of the Paris climate deal - with The White House announcing it is close to a decision on the global agreement, and Donald Trump tweeting on the weekend his intention to make a final call this week.
Now climate experts at The Australian National University have weighed in on what the potential global fallout would be if Trump does pull the pin.
I will make my final decision on the Paris Accord next week!
— Donald J. Trump (@realDonaldTrump) May 27, 2017
Associate Professor Nerilie Abram from ANU Research School of Earth Sciences
"There is no doubt in the science. The greenhouse gases that we are putting into Earth's atmosphere are changing our climate. Heatwaves are worsening, oceans are rising, rainfall patterns are being altered. The Paris Agreement recognises the very ambitious global efforts that are needed to rein in the problems we have caused.
"There is one certainty in this: regardless of whether or not the US leaves the Paris Agreement, if we keep polluting our atmosphere then climate change will continue to worsen. And the worse we let it get the more destructive and expensive it will be.
"More than a quarter of the carbon dioxide that has been added to our atmosphere since the Industrial Revolution has come from the US. So there is a very strong moral obligation for the US to be part of the global solution."
Dr Luke Kemp from ANU Fenner School of Environment and Society
"Having the US remain under the Paris Agreement would reveal the weaknesses of the agreement, prevent new opportunities from emerging, and gift greater leverage to a recalcitrant administration.
"The Paris Agreement is procedural: it requires a new pledge every five years, but doesn't limit the actions of the US. The US will likely miss its target and cut climate financing regardless of Paris.
"Countries are more likely to withdraw or renege on their actions because the US misses its target, eliminates its financing and reveals how weak the Paris Agreement really is.
"A US withdrawal could trigger new opportunities to emerge, such as carbon border adjustments and forceful leadership from the EU and China.
"While the Paris Agreement is fragile, international climate action can be anti-fragile: the shock of Trump could make action stronger by allowing trade measures and new, emboldened leadership to blossom."
Professor Mark Howden, Director of the ANU Climate Change Institute
"The best outcome for both the US and the rest of the world is for the US to remain in both the Paris Agreement and the UNFCCC and to play a constructive and progressive role.
"Obstructive behavior in the climate change negotiation arena is likely to reduce support for other key US agendas from key diplomatic blocs. And aligning US domestic energy and innovation policy with its stance on the Paris Agreement policy will result in large opportunity costs from missing the wave of innovation that is emerging to address climate change issues.
"A US withdrawal may also act to energise not only other countries but also states, cities, businesses and communities who wish to take up the baton of positive and constructive leadership and the economic, social and environmental opportunities that addressing climate change could bring."
Professor Frank Jotzo, ANU Crawford School of Public Policy
"Regardless of whether the United States stay in the Paris Agreement or not, most other nations are likely to go ahead with their own national climate action plans. Crucially, this includes China. The case for a transition to low-emissions economies is compelling, and technological progress especially in renewable energies is making that transition ever more attractive.
"The Trump administration's stance against action is sand in the gears of climate change action. If the United States pull out, this will amplify the signalling effect that Trump has already had in boosting fossil fuels through rhetoric and removing regulations.
"If the United States stays in the Paris Agreement, America could stifle progress from within, by demanding changes and obstructing implementation. In either case, the Trump administration is unlikely to fulfil previous pledges for climate finance and cutting US greenhouse gas emissions.
"The worst scenario would be if Trump decided that the US should leave the UN Framework Convention on Climate Change. Exiting the UNFCCC would remove the US entirely from the global climate-change process. It could then be difficult for the US to re-enter the Convention later, under a new President."
Dr Christian Downie, ANU School of Regulation and Global Governance (RegNet)
"The US position on the Paris climate agreement will likely have ramifications around the globe. In the absence of US leadership, the question is: who will step up?
"If Europe and China together decide to fill the vacuum left by the United States, they could form a powerful bloc to lead global efforts against climate change. Leaders in Europe have already hinted at retaliation should the United States withdraw from the Paris Agreement, including a carbon tax on US imports.
"Should China follow the same path, together they would represent the largest import market in the world, giving them a very large stick to wave at America. An EU-China bloc could also help to ensure that there is less potential for other nations, including Australia, to follow the United States down the do-nothing path."
Associate Professor Mahendra Kumar, Adjunct Professor at the ANU Climate Change Institute
"It is better for US to withdraw from the Paris Accord completely rather than remain and undermine it from within. We cannot afford to have a ‘team’ player, working against the team’s strategy.
"The threat to revise the Intended Nationally Determined Contribution downwards goes against the spirit of the agreement and the clearly enunciated principle that any revisions should build on existing targets, and be ratcheted up to meet the temperature goal. If the US remains in the Paris Accord and backslides, there needs to be a mechanism for mitigating against other countries backsliding.
"There is a real danger that other countries, including Australia, will use a US Paris exit to say the agreement is dead and they should likewise reconsider its commitments. So we should do what we can to make clear to the Australian Government that in the event of a US withdrawal, Australia must immediately reaffirm its commitment to Paris and strengthen its woefully inadequate contributions."
Dr Jonathan Pickering, Visiting Fellow at the ANU Crawford School of Public Policy
"If the US were committed to acting on climate change, the case for staying in the Paris Agreement would be clear. But given the current Administration's savage rollback of Obama-era climate policies, the choice is much tougher. Which is the lesser evil for global cooperation on climate change: to have a recalcitrant major power in the Agreement or out of it?
"There's a major risk that continuing US participation in the Agreement will upset the delicate balance of commitments that countries reached in Paris.
"But withdrawing from the Agreement altogether could be even worse. It will provide cover for reluctant countries to exit, water down their targets or simply fail to join, just as Australia used US non-participation as an excuse to stay out of the Kyoto Protocol. And the violation of trust resulting from US withdrawal could further jeopardise prospects for global cooperation on other priorities."