By David McHugh

WORLD powers have lined up against 
US President Donald Trump on climate change as they reaffirmed their support for international efforts to fight global warming.
The final statement of the G20 summit in Hamburg, Germany, underlined that the other countries and the European Union supported the Paris climate agreement rejected by Mr Trump.
They called the deal to reduce greenhouse gases “irreversible” and vowed to implement it quickly and without exception.
The other countries, from European powers such as Germany to emerging ones such as China and energy producers such as Saudi Arabia, dismissively “took note” of the US position, which was boxed off in a separate paragraph.
German Chancellor Angela Merkel said the US position was “regrettable” but the summit had achieved “good results in some areas”, and cited a hard-won agreement on trade that does include Mr Trump and the United States.
On trade, difficult talks yielded the preservation of the G20’s condemnation of protectionism, a statement that has been a hallmark of the group’s efforts to combat the global financial crisis and the after-effects of the Great Recession.
The group added new elements, however: an acknowledgment that trade must be “reciprocal and mutually advantageous” and that countries could use “legitimate trade defence instruments” if they are being taken advantage of.
That echoes concerns raised by Mr Trump, who was attending his first G20.
He has said trade must be fair as well as open and must benefit American companies and workers and has focused on trade relationships where other countries run large surpluses with the US, meaning they sell more to US consumers than they buy from American companies.
But pro-trade officials from the EU pointed out that the language in the G20 statement contains no departure from the current global system of regulation, which already allows countries to take defensive measures within the rules of the World Trade Organisation.
Those can include import taxes that offset unfair practices such as government subsidies or below-cost pricing.
The EU demonstrated its willingness to move ahead with free trade despite Mr Trump by announcing a trade agreement with Japan on the eve of the summit. On climate, summit deputies put together a three-part fudge that everyone could sign.
That meant a first section with a broad pledge to fight climate change in general; a separate paragraph carved out that acknowledged the US did not support the Paris deal; and a third paragraph in which the other 19 members reaffirmed their support for the deal.
The results of the summit are not absolutely decisive, on either the trade or the climate issue.
The no-protection pledge was often violated, increasingly in harder-to-detect ways such as tax breaks for home industries rather than obvious import taxes.
Meanwhile, failure to agree on climate does not stop countries from moving ahead in meeting the Paris agreement’s goals, or exceed them if they want to.
Additionally, US states and private companies can pursue lower emissions on their own.
G20 agreements are statements of intent and rely on governments themselves to follow through. 
Other deals at the summit included an agreement to press internet providers to detect and remove extremist content as a way of fighting terrorist incitement and recruiting.
John Kirton, co-director of the G20 Research Group at the University of Toronto’s Munk School of Global Affairs, called the summit a “very solid success”, pointing to broad agreement on the agenda, much of it focusing on less controversial issues.
The meetings competed for attention with rioting by anti-capitalist demonstrators outside the heavily secured Hamburg Messe convention centre.
Rioters set up street barricades, looted supermarkets and attacked police with catapults and firebombs.
Around 186 protesters were arrested, even after G20 leaders had left the city. Cars were torched, stores looted, bikes burned in street barricades and windows smashed during the three days of violence. Some 476 officers were injured.
German police again used water cannon against rioters who attacked them with iron rods and stones ripped from pavements. Apart from the arrests, police detained another 225 people temporarily.
Foreign minister Sigmar Gabriel condemned the violence and said a Europe-wide investigative team should search for suspects.
He added: “Germany’s reputation is severely affected internationally by the events in Hamburg.”
The city’s police chief, Ralf Meyer, said he was proud of the 20,000 officers who managed to provide security for the many international leaders and their delegations.
But it was deplorable so many of the officers were injured and that the violent riots could not be prevented, he added.
The city’s interior minister, Andy Grote, said “We had to deal – detached from the actual events at the summit – with ruthless acts of violence by criminals.”
The overwhelming majority of the tens of thousands who took to the streets protested peacefully.