Environment heads of the G7 industrial nations converged on Bologna Sunday with US President Donald Trump's oil-friendly advocate Scott Pruitt facing international calls to rethink Trump's recent decision to quit the 2015 UN climate pact .

Host Italian Environment Minister Gian Luca Galletti said G7 countries bore crucial responsibility for the planet. "The international community awaits our message," he added.

Visiting San Francisco on Friday, German environment minister Barbara Hendricks and California's Jerry Brown, governor of the USA's wealthiest state, agreed to work together to keep Paris on track.

Hendricks (pictured above, left) said it was an "important signal" that many US states, cities and firms still adhered to Paris' goal of curbing climate-warming carbon emissions.

Top Beijing welcome for California's Brown

Brown had just returned from a week-long red carpet visit to China, where the Californian bypassed Washington by agreeing clean energy and research projects with Beijing.

Germany's Barbara Hendricks visited Jerry Brown earlier this month in California

Brown met Chinese President Xi Jinping, while US Energy Secretary Rick Perry, who made a parallel trip, was reduced to a meeting with China's number seven, Zhang Gaoli.

Aside from Hendricks, also expected in Bologna was Scott Pruitt, Trump's choice for the US Environmental Protection Agency (EPA), and French President Emmanuel Macron's cabinet nominee, Greens campaigner Nicolas Hulot.

'Cohesive approach,' urges Japan

Ahead of the G7's two-day Bologna encounter, Japan's environment minister Koichi Yamamoto had remarked over Trump's pullout: "The world is already turning carbon-free and I think there will be no change to this broad trend."

Addressing Sunday's opening session, Yamamoto said: "The G7 countries have to have a cohesive approach."

The Bologna discussions will also be attended by representatives of Chile, the Maldives, Ethiopia and Rwanda, four nations with strong interest in stemming climate change.

Pruitt tweeted in 2014 that 'global warming is an expensive hoax'

An organizer of a Bologna demonstration due on Sunday afternoon, Giacomo Cossu, said: "A lot of people are very upset about Trump's decision."

Trump to be 'isolated'

German news magazine Der Spiegel reported Saturday that officials close to Chancellor Angela Merkel who are organizing next month's larger G20 summit in Hamburg had prepared a draft declaration reaffirming the Paris accord.

Der Spiegel said the aim had been to "isolate" Trump, although Canada's Prime Minister Justin Trudeau had urged caution in formulating the text.

When G7 leaders met in Sicily last month, six members - Britain, Canada, France, Germany, Italy and Japan - vowed to continue climate rescue efforts.

Devastating consequences

Scientists assisting the Bonn-based UN climate agency have long warned that failure to restrain climate change will have devastating consequences.

Scenarios include coastal inundation through sea level rise, extreme storms, droughts and heat waves, which are likely to trigger new conflicts and migration.

Cooling off at Allahabad railway station in northern India

Alarming Indian heat wave findings

A new heat wave study for India published Wednesday in the journal Science Advances warned that the risk of massive mortality events had shot up by 146 percent between 1960 and 2009.

In May last year, India recorded an unprecedented high of 52.4 degrees Celcius (126.3 degrees Fahrenheit) in the western city of Jaisalmer.

The vast majority of India's 1.25 billion population are poor and have few options to mitigate sweltering temperatures, for example, through air conditioners.

ipj/jlw (AP, AFP, dpa)