Republicans are likely to hold a narrow majority in the Senate and are likely to seek to block Mr Biden's agenda if he is president,according to Kate Larsen,a director in the White House Council on Environmental Quality during the Obama administration.

However,the president controls foreign policy and can re-commit the country to the Paris Agreement.

Ms Larsen said given the Biden presidency may not be able to swiftly pass emissions reduction reforms through the Senate,it would not be able to commit under Paris to ambitious emission reduction goals.

"It may want to be more cautious … about what kind of new target it would take on and how it would communicate that internationally,"she said.

"Getting to 100 per cent (emissions reduction) is going to be a big challenge that would likely require congressional activity,and with the Senate looking like it will stay Republican,it's unclear how that would happen."

Ms Larsen said the Senate constraints on creating laws to drive emissions reduction could see a Biden administration"returning in a humble way"to the international climate accord.

"The US needs to approach climate leadership with a little bit more humility than we have in the past,"Ms Larsen said."I know that's not a great American trait,but walking in as the returning champions after these four years is not something that we can or should do."

However,pressure is mounting on Australia,which has only committed to reach net zero by sometime in the second half of the century,but has not set a firm deadline. Countries that are pursuing a deadline may seek to impose cross-border tariffs by countries which are yet to commit to a timeline.

China,Japan,Britain and South Korea,which account for more than $310 billion in Australian annual trade between them,have all now adopted net zero emissions target by 2050 or 2060.