WASHINGTON (REUTERS) - Ten Democratic US presidential hopefuls outlined plans to tackle climate change on Wednesday (Sept 4) in a series of CNN town halls.

Below are the main climate strategies of the candidates who participated in the event.

JOE BIDEN

Joe Biden, the front-runner for the Democratic nomination to face Republican President Donald Trump in the November 2020 election, touts a US$1.7 trillion (S$2.36 trillion) plan to set the United States on a course to achieve 100 per cent clean energy and net-zero emissions by 2050.

The plan calls for the installation of 500,000 electric vehicle charging stations by 2030, rejoining the Paris Climate Agreement and boosting targets, and offers US$400 billion for research and development in clean technology. The plan did not call for quitting fossil fuels - instead investing money in carbon capture and sequestration that could give a lifeline to coal and gas plants.

Biden's rivals accused him of offering a "middle-ground" plan that would not achieve decarbonisation goals. When asked by the moderator at a recent debate if his administration would end the use of fossil fuels, he said: "We would work it out. We would make sure it's eliminated, and no more subsidies for either one of those, either - any fossil fuel."

BERNIE SANDERS

"We need a president who welcomes their hatred," US Senator Bernie Sanders of Vermont says in his plan about fossil-fuel executives he sees as blocking action on climate. His plan, dubbed the Green New Deal after a resolution sponsored by progressives in Congress, mobilises US$16.3 trillion to generate all US electricity from renewable sources by 2030 and create publicly owned utilities.

Gasoline-fuelled cars get phased out, while electric car-charging stations and public transport get support. The plan bans new nuclear plants, currently the top source of carbon-free power, and the burying of carbon emissions from fossil fuels, a technique favoured by the United Nations.

Both of those could face backlash by those concerned about jobs in those industries.

ELIZABETH WARREN

US Senator Elizabeth Warren of Massachusetts outlined US$3 trillion in federal investments on Tuesday that builds on the plan of Jay Inslee, the Washington state governor who anchored his campaign on climate, but dropped out in August. Warren has also woven climate into other policies. Her economic plan blends it with industrial policy, investing in green research, manufacturing and exports, and creating a federal procurement program for American-made renewable or emission-free energy for federal and state use and export.

Some of her plan would be funded by reversing Republican tax cuts that largely benefit businesses and the wealthy. Warren's plan seeks 100 per cent zero emissions for most new vehicles by 2030 and 100 per cent zero emissions in electricity generation by 2035.

PETE BUTTIGIEG

At 37, Pete Buttigieg is attempting to win voters by reminding them that his generation faces the most risks from climate change. The mayor of South Bend, Indiana, supports a national carbon tax and dividend, a method of directing revenues from fees on fossil fuels to families most affected by an energy transition. A military veteran, Buttigieg has emphasised climate risks to security. He backs a "climate corps" to get thousands of young people working on building community resilience to extreme weather.

KAMALA HARRIS

US Senator Kamala Harris of California released a US$10 trillion climate plan on Wednesday that draws on her experience prosecuting polluters as a former California attorney general.

Her plan would end federal support for the fossil fuel industry, put a fee on pollution and increase penalties for emitters. She also backs protecting poor communities from storms, floods and droughts. Harris came under fire from environmentalists by initially declining to participate in Wednesday's town hall to attend a fundraiser.

BETO O'ROURKE

Beto O'Rourke's first policy initiative was a US$5 trillion climate plan.

Yet O'Rourke, a former US congressman from Texas, is also pragmatic on climate. His plan seeks net-zero US carbon emissions by 2050, which many environmentalists complain is less ambitious than the Green New Deal resolution, which aspired to make such cuts by 2030. O'Rourke voted against a ban on federal money to research offshore oil drilling, and for lifting the ban on crude oil exports, not unusual positions for a Texas Democrat. His climate plan does not rule out nuclear power or carbon capture, indications of flexibility.

CORY BOOKER

US Senator Cory Booker of New Jersey during the second Democratic debate in July inserted himself into a brief climate exchange by taking a dig at rivals who promise to return the United States to the Paris Climate Agreement as their answer for not addressing the issue. "Nobody should get applause for rejoining the Paris climate accords. That is kindergarten," he said. Booker released a US$3 trillion plan on Tuesday including a White House-coordinated environmental justice fund to focus on defending at-risk communities from environmental threats.

Booker would also ban fracking and reinstate the ban on exporting crude oil. He also introduced legislation focused on "voluntary farm and ranch conservation practices, massive reforestation, and wetlands restoration."

Like most of his Democratic rivals in the Senate, Booker endorsed the Green New Deal.

JULIAN CASTRO

Julian Castro, the housing secretary under President Barack Obama, released a plan on Tuesday outlining federal, state and private investments of US$10 trillion over 10 years to transition from fossil fuels and create 10 million jobs. Castro wants to establish a US$200 billion green infrastructure fund as part of a wider housing plan to help defend communities against climate change damages. Castro also seeks to guarantee healthcare and defend pensions for coal miners and bring economic development to communities hit by shutdowns in fossil fuel infrastructure.

As a former mayor of San Antonio, Castro helped the Texas city close a large coal plant and set renewable energy targets. But environmentalists have criticised him for backing fracking in the region, which he supported for the jobs.

AMY KLOBUCHAR

Amy Klobuchar, a US senator from Minnesota, launched her 2020 campaign in the midst of a snowstorm in February, prompting Trump to take to Twitter to mock her for fighting global warming while standing in freezing temperatures. Klobuchar was one of the early backers in the Senate of the Green New Deal and has vowed to use her first 100 days in office to issue executive actions to tackle climate change by restoring some Obama-era policies. Playing to her strength as a Midwestern politician, she has called for boosting the Renewable Fuel Standard, a policy for corn-producing states like Iowa and Nebraska.

ANDREW YANG

Entrepreneur Andrew Yang said at the second presidential debate he would tackle climate change by paying people hit by rising seas and flooding to move to higher ground. His US$4.87 trillion plan offers US$40 billion in loans and subsidies to people who wish to relocate. Yang said his plan's price tag pales in comparison to the costs of climate change's health and environmental impacts. His plan sets a target of net-zero US emissions by 2050. It calls for a modernisation of the electric grid, debt forgiveness for rural electric co-ops to switch to renewables, and a carbon tax on polluters.