By Agence France-Presse
Trump's protectionist policies that have seen him slap steep tariffs on steel and aluminum, angering allies such as the EU, Canada and Mexico, already looked set to fashion discussions between finance ministers and central bankers from the world's 20 leading economies during two days of meetings.
That is even more the case after his latest Twitter outburst on Friday saw him accuse the EU and China of "manipulating their currencies and interest rates lower," while he also took aim at the US Federal Reserve for hiking interest rates, complaining that it eroded "our big competitive edge."
China and the US have no plans for bilateral talks, according to US Treasury Secretary Steven Mnuchin, who has vowed to "respond to concerns on US trade policies" when he meets with fellow ministers.
But China will be a hot topic as Group of Seven ministers hold a one-hour session on the margins of the wider meeting, not least after Trump threatened to crank up punitive tariffs against the country to include the entire $500 billion in goods the US imports from the Asian powerhouse.
As well as his steel and aluminum duties, and threats to likewise hit foreign car imports with tariffs, Trump has already slapped China with a 25 percent levy on $34 billion in goods, with another $16 billion on the way.
- 'Very serious' -
Other than announcing counter-measures, China has kept relatively quiet over Trump's various threats -- perhaps safe in the knowledge that his tariffs are a drop in the bucket next to their expected $2.4 trillion exports for 2018.
But German Chancellor Angela Merkel warned that the EU was "ready" to respond to the US should more excises be forthcoming, describing current trade tensions as "very serious."
International Monetary Fund chief Christine Lagarde, whose press conference will kick off activities on Saturday morning, said earlier this week that increasing trade restrictions pose "the greatest near-term threat" to the world economy, despite projected growth of 3.9 percent through 2019.
She also warned Trump that "the US economy is especially vulnerable" due to "retaliatory measures."
IMF economists say that in a worst case scenario $430 billion -- a half point -- could be cut off global GDP in 2020 if all tariff threats and retaliation are implemented.
Others are also worried about Trump's measures, including India, which alongside China, Brazil, Russia and South Africa make up the five emerging market BRICS countries, all of which are G20 members.
"All BRICS members have benefitted from globalization. All of them need finance and capital inflows," said Sreeram Chaulia, dean at Delhi's Jindal School of International Affairs.
"Trump is trying to put a brake on trade and finance. We rely on international capital movement and inward FDI, Trump wants to stop it."
'History is clear'
The economic problems plaguing a number of emerging markets will occupy ministers, particularly given that host nation Argentina recently secured a $50 billion IMF loan to try to stabilize its economy, after the peso plunged 35 percent between April and June.
"The situation facing certain emerging markets is more delicate with the rise of the dollar and the question of capital flows," a French source told AFP.
As well as the dollar, rising oil prices and US interest rates have helped fuel the capital flight from emerging economies such as Brazil and Argentina, with investors taking out $14 billion between May and June.
"The meeting will take place against the backdrop of ongoing financial vulnerabilities in emerging market economies and global trade tensions," said Australian Treasurer Scott Morrison.
He headed to Buenos Aires planning to urge G20 members to keep markets open.
"History is clear: when trade barriers go up, growth and jobs go down," he added.
Economist Rubens Barbosa, former Brazilian ambassador to Washington and London, says Brazil will try to defend multilateralism in international trade -- notably as upheld by the World Trade Organization.
"In Buenos Aires, what will be on the table is protectionism and the strengthening of the WTO from the point of view of emerging countries such as Brazil," he said.