Image source, Getty Images

A key architect of the Paris Climate Agreement has called on the rest of the world to plough on with climate action despite the US withdrawal from the treaty.

Professor Laurence Tubiana, who served as 's special representative for the 2015 COP Climate Change Conference in Paris, spoke to our colleagues on Radio 4's World at One programme a little earlier.

"We should not be frightened by shouting, or the declaration of what the president of the United States has decided. There is no more one hegemon, or one country leading the world. That is over. So let's be courageous and stand up because we can't just ignore it [climate change]," she said.

You can listen to Tubiana's full interview in this recording of the World at One programme.

From 11:00 EST (16:00 GMT), our experts and correspondents will be answering your questions live on what to expect from Donald Trump's second term.

You can get in touch using #BBCYourQuestions - or email [email protected] - and you'll be able to watch the Q&A live on the BBC News Channel and at the top of this page.

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Trump has wasted no time issuing executive actions that could significantly reshape the US's policies.

But what are they?

Executive actions include executive orders, which are legally-binding, and other presidential directives like proclamations, which are usually not.

An executive order is a written order - issued by the president to the federal government - which does not require congressional approval.

Orders range from dramatic reverses of policy, to ordinary business.

The power to make these orders comes from Article II of the US constitution, external, which states: "The executive power shall be vested in a president of the United States of America." If an order is deemed to stray outside the boundaries of what is acceptable, it can be subject to a legal review.

During his previous term, Trump signed 220 executive orders, some of which were challenged in the courts.

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One of President Trump's first trips will be to Los Angeles, following the deadly and destructive wildfires which broke out two weeks ago.

At his pre-inauguration rally, Trump said he'll visit California on Friday.

Governor of California Gavin Newsom said he'll "look forward to President Trump’s visit to Los Angeles and his mobilization of the full weight of the federal government to help our fellow Americans recover and rebuild" in a statement on Monday.

Republican House speaker, Mike Johnson, said he believes "conditions" should be placed on the federal disaster aid allocated for communities affected by the wildfires.

Johnson and Trump are due to meet this afternoon.

The 45th and now 47th president of the United States is wasting no time putting his plans into action.

What does Donald Trump mean when he promises a “new golden age for America”? Why is he g so many executive orders?

Justin, Sarah, Marianna, and Anthony are together in Washington to unpack the news as it breaks.

• You can listen to the full episode here

Dominic Hughes
Health correspondent

The most obvious impact of the US withdrawal from the WHO will be on the budget of the global health body.

Of 196 member states, the US is by far the largest individual funder, contributing almost a fifth of the total budget.

If that goes, and no other nations step up to fill the gap, the ability of the WHO to respond to emergencies such as an Ebola outbreak, or mPox – let alone another Covid-19-style pandemic – could be compromised.

Some scientists worry the US will now be left isolated when it comes to programmes such as pandemic preparedness and seasonal influenza strain sequencing, used to develop annual flu jabs.

Others argue the US withdrawal could prompt further reforms of how the WHO works, making it a body that better serves the public health needs of people around the globe.

But there's little sign that will be enough to convince the president to reverse his decision.

Image source, Reuters

Donald Trump has already issued a flurry of executive orders on everything from immigration and climate to pardoning people convicted over the 2021 Capitol riot.

Here's an overview of some of the new president's actions so far - and here's the full list plus added context.

Immigration

• He has declared a national emergency at the southern border
• Trump ordered that officials deny the right to citizenship to the children of migrants either in the US illegally or on temporary visas
• Gangs and cartels have been designated as foreign terrorist organisations

Climate and energy

• Trump has signed off on withdrawing from the Paris climate agreement - again
• He has declared a "national energy emergency" and vowed to "drill, baby, drill" for more fossil fuels

World Health Organization

• Trump signed an executive order to begin the process of withdrawing the US from the UN's health body, the World Health Organization (WHO)

Diversity and gender

• Trump has declared that the US will only recognise "two sexes, male and female"
• He has also halted all "diversity, equity and inclusion" (DEI) programmes within the federal government

2021 Capitol riot

• The president has issued pardons for nearly 1,600 of his ers who were arrested in the riot at the US Capitol in 2021
• He also commuted sentences for of the Oath Keepers and Proud Boys, far-right groups who were convicted of seditious conspiracy in relation to the riot

Economy

• Trump has signed a directive asking every US federal department and agency to address the cost of living

Trump is back in the Oval Office - and the long tradition of presidential redecoration is under way.

In redecorating, the president symbolises their goals for the coming four years by putting their own personal spin on the room.

Trump's creative licence shows itself in a red valet button, used by the president to request a butler bring his favourite drink: Diet Coke.

He has also reintroduced a bust of Winston Churchill - which was removed by Biden. The statue returns to the White House exactly where it was four years ago.

But Trump has kept some of former President Joe Biden's touches, including a portrait of Benjamin Franklin and a sculpture of Martin Luther King.

The office has been redone with silver figurines, a new carpet, and a personalised paperweight.

Image source, Reuters

Rachel Flynn
Live reporter

Image source, Reuters

After a mammoth inauguration day filled with pomp and processes, US President Donald Trump and First Lady Melania Trump woke up this morning in the White House.

We don't know much yet about his agenda today - but here's what we do know:

• At 11:00 local time (16:00 GMT) Trump will attend the National Prayer Service at the Washington National Cathedral. The cathedral says today's service will "offer prayers of thanksgiving for our democracy and seek God’s guidance in the years ahead"
• This afternoon, the president is set to host key Republicans, including House Speaker Mike Johnson and Senate Majority Leader John Thune

Trump has also pledged to focus on deportations on his first day, after unveiling an executive order to deport millions of "criminal aliens".

As soon as we have more on this, you will too. Stick with us.

The second Trump era has truly begunpublished at 12:22 Greenwich Mean Time 21 January

12:22 GMT 21 January

Anthony Zurcher
North America correspondent

Donald Trump's inaugural address was a mix of promises – and contradictions – that underlined some of the opportunities and challenges the new president will face in his second term in office.

He started talking at a little after noon on Monday, and it seemed at times like he didn't stop talking – at ad-libbed remarks later at the Capitol, at his indoor parade rally at a downtown sports arena and at the White House executive order g – until well into the evening.

Through it all, Trump demonstrated the kind of dramatic flair and penchant for controversy and confrontation that has energised his ers and infuriated his critics.

Trump returns to power with a team that has a detailed strategy for governing and an aggressive agenda to pursue. Trump himself, however, can still be as unpredictable and unfocused as ever – making remarks that could represent new policy or just a momentary distraction.

The second Trump era has truly begun.

• Read Anthony Zurcher's full analysis here

Elon Musk caused outrage over a one-armed gesture he gave during a speech celebrating the inauguration of Donald Trump.

Musk thanked the crowd for "making it happen", before placing his right hand over his heart and then thrusting the same arm out into air straight ahead of him. He then turned and repeated the action for those sitting behind him.

Many on X, the social medial platform he owns, have likened the gesture to a Nazi salute.

In response, Musk posted on X: "Frankly, they need better dirty tricks. The 'everyone is Hitler' attack is sooo tired."

Musk, the world's richest man and a close ally of President Trump, was speaking at the Capital One Arena in Washington DC when he made the gesture.

"My heart goes out to you. It is thanks to you that the future of civilisation is assured," he said, after giving the second one-armed salute.

There was immediate backlash on social media.

• Musk responds after backlash over gesture at Trump rally

Nabiha Ahmed
Live reporter

Papers were signed and oaths were taken - and photographers captured all the key moments as US President Donald Trump returned to Washington.

From swords to shut-eye, we've rounded up some key moments caught on camera.

Image source, Reuters

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Holly Honderich
Reporting from Washington DC

An optimistic start - then a grim assessment of America

"The golden age of America begins right now," Trump said.

He later described the outgoing istration as a "radical and corrupt establishment".

Laundry list of promises for the first 100 days

Trump said he would declare a national emergency at the southern border and deploy national troops for immigration enforcement.

'Saved by God' after assassination attempt

"Just a few months ago, in a beautiful Pennsylvania field, an assassin's bullet ripped through my ear, but I felt then and believe even more so now, that my life was saved for a reason," he said.

"I was saved by God to make America great again."

Mars and the Panama Canal

Trump said he wanted the Panama Canal under US control, falsely claiming it is currently operated by China.

Trump also looked upwards, vowing to "pursue our manifest destiny into the stars, to plant the stars and stripes on the planet Mars".

'There are only two genders'

"It will henceforth be the official policy of the United States government that there are only two genders: male and female," Trump told his audience, to rounds of applause.

Read more on Trump's inauguration speech

Barron Trump, the president's son with First Lady Melania Trump, is among those returning to the White House.

Last time his father was inaugurated, Barron was just 10. He's now a university student - and very tall.

Trump has credited Barron for reaching voters by suggesting an appearance on the popular podcast The Joe Rogan Experience. Yesterday, Trump called Barron his "very tall son", prompting cheers from the audience at an inauguration event.

Image source, Reuters

It's 06:00 in Washington DC (11:00 GMT) and the US is beginning to wake up to the first full day of the new Trump istration.

The president spent his first few hours back in the White House issuing a flurry of executive orders and presidential pardons.

Among his early moves was an order to deport millions of "criminal aliens". Trump also declared an emergency on the US-Mexico border and designated drug cartels as terrorist organisations.

More globally, Trump ordered that the US begin its withdrawal from the Paris climate agreement and the World Health Organization. He also signed an order addressing gender, declaring that there are only two genders - male and female - and cannot be changed.

Trump has pardoned nearly 1,600 defendants involved with storming the Capitol on 6 January 2021. Some are expected to be released from prison later today.

We'll be watching for developments throughout the day from the new US government. Stay with us.

Samuel Lando
BBC Monitoring

There’s a sense of apprehension and pessimism over Donald Trump’s return to power in mainstream media across much of sub-Saharan Africa.

Trump’s decision to withdraw from the WHO was described today by Uganda’s Chimp Reports news website, external as potentially having “profound” impacts on Africa, since the US government is one of the largest donors to global health programmes.

Tanzania has just confirmed its first case of the Ebola-like Marburg virus, and the continent is still struggling to contain major infectious disease outbreaks like mpox.

There is anxiety in some news outlets over Trump’s plans to deport “millions” of illegal immigrants, external, while the idea of an official two-gender policy has been greeted with widespread approval on social media in Africa.

The US president remains popular in many evangelical Christian communities in sub-Saharan Africa.

Stephen McDonell
China correspondent, reporting from Beijing

China’s foreign ministry spokesperson says Beijing is “concerned” that the US is pulling out of the Paris agreement for a second time.

At a regular press briefing, Guo Jiakun contrasted this to his own country, which he said was “actively responding” to global warming.

He also criticised Washington for leaving the World Health Organization when it should be strengthened.

Nevertheless, Guo says there's a “huge space for trade co-operation” between the world’s superpowers, despite Donald Trump’s threats to impose new rounds of tariffs.

In a post on X, Dr Tedros Ghebreysus, the head of the World Health Organization (WHO), is responding to the Trump's executive order for the US to part ways with the organization.

In a statement, he writes that the WHO "regrets the announcement that the United States of America intends to withdraw from the Organization."

He adds that the US was among the founding of the WHO and has shaped its work since.

"We hope the United States will reconsider and we look forward to engaging in constructive dialogue to maintain the partnership between the USA and WHO, for the benefit of the health and well-being of millions of people around the globe."

The US is the biggest donor to the WHO and ed for 18% of its budget in 2023.

Image source, Reuters

Gabriela Pomeroy
Live reporter

In a series of executive orders, Trump has promised to deport millions of "criminal aliens" and declared a "national emergency" at the country's border with Mexico.

Scott Lucas, professor of US and international politics at the Clinton Institute at University College Dublin, has been telling us which executive actions will become law immediately.

The US system of government has congressional, judicial and executive powers, he says. "Trump is using his executive power by declaring these orders". As long as an action doesn't need approval from Congress, he explains, it is legal immediately.

"Trump’s executive orders on immigration can start straight away, but there will be legal challenges", Lucas says. The president "is trying to end birthright citizenship" - but people born in America are American citizens, something "that is enshrined in the constitution", he adds.

"Is it legal for him to just end this? He will have a legal battle over this one," Lucas predicts. "People will say they have a right to stay here."

Trump now oversees US Customs and Border Protection, as well as Immigration and Customs Enforcement (Ice).

That means he can order both departments to "deport about 12-13m people in the USA who are undocumented – he can just say 'go get ‘em.'"

"But I don’t think it is feasible to get rid of millions," Lucas adds. "It will cost billions and will cause chaos."

Image source, EPA