People around the world beset by the impacts of global warming like droughts, heat waves and storm surges are calling for "climate justice," and many are pleading their cases in court.
Globally, there are at least 1,000 active legal cases related to climate change, more than two-thirds of them in the United States, according to a recent tally from the Grantham Research Institute on Climate Change and the Environment, in London.
A summit Tuesday in Paris -- with more than 50 heads of state attending -- on how to finance the transition to a low-carbon economy will be followed the next day by a climate justice forum.
The climate justice movement highlights the fact that rich nations are overwhelmingly to blame for causing climate change, but that poor ones have been the first to cope with its impacts.
The 1992 UN Framework Convention on Climate Change (UNFCCC) recognised that inequality, declaring that developed countries bear a larger responsibility for fixing the problem.
After a climate justice "summit" in The Hague in 2000, a coalition of global non-governmental organisations (NGOs) -- which play a crucial role in chaneling grassroots activism -- adopted 27 principles.
These included the right to not suffer climate change impacts, a moratorium on new fossil fuel exploration, access to affordable and sustainable energy, the notion that rich nations and industry owe humanity an "ecological debt".
"Climate justice affirms the rights of unborn generations to natural resources, a stable climate and a healthy planet," they declared.
These ideas slowly gravitated from the fringes toward the centre of formal UN negotiations -- and finally into the preamble of the 2015 Paris Agreement, the 196-nation treaty that enjoins the world to cap global warming at "well under" two degrees Celsius (3.6 degrees Fahrenheit).
In parallel to the diplomatic arena, citizens and civic groups also tested the concept's power within a legal framework.
Some plaintiffs have targeted governments, while others have taken on individual companies. A few have made headlines:
- In 2015, a landmark court ruling in the Netherlands ordered the government to slash greenhouse gases a quarter by 2020. The case was brought by 900 Dutch citizens. The government is appealing.
- Last month, a German court agreed to hear a Peruvian farmer's case against energy giant RWE over climate change damage in the Andes, a decision hailed by campaigners as a "historic breakthrough".
Farmer Saul Luciano Lliuya says that RWE -- one of the world's top emitters of climate-altering carbon dioxide -- must share in the cost of protecting his hometown Huaraz from a glacier lake overflowing from melted snow and ice.
- Also in 2015, 21 young people sued the US federal government for allegedly violating their constitutional rights by failing to ensure a livable future. First under former president Barack Obama, and then under Donald Trump, the government has tried -- and failed -- to get the case thrown out.
If it goes to trial, as seems likely, "the judge will decide two things," said Daniel Galpern, one of the attorneys for the plaintiffs.
"Has the United States in fact violated these fundamental constitutional rights? And, if so, whether to compel the government to come up with a plan to move us from disaster to security," he added.
The case could well go to the Supreme Court, he told AFP.
The Paris Agreement "recognises the importance... of addressing loss and damage" caused by climate change, and has set up a mechanism to do so.
At the same time, however, this provision "does not involve or provide a basis for any liability or compensation," according to a "decision" annexed to the treaty.
This does not mean that rich nations are off the hook, analysts say.
As some island nations literally sink beneath rising seas, pressure is mounting for a clear commitment for the rescue of climate-damaged economies and societies.
On the legal front, plaintiffs are pointing to scientific evidence that extreme weather events -- mega-storms, heat waves, droughts, flooding -- can be directly linked to climate change.
Other research apportions historic responsibility for greenhouse gas emissions, whether to countries or companies.
A 2014 study in Climatic Change, for example, calculated that accumulated CO2 and methane pollution stemming from oil, gas and coal produced by 90 major energy companies accounts for nearly two-thirds of all greenhouse gas emissions since 1850.
RWE -- the firm being sued by the Peruvian farmer -- was found to have emitted 0.47 percent of the total.
"The possibility of assigning contributions of individual regions to damage could have the potential to reshape environmental litigation," a quartet of scientists wrote in the journal Nature Climate Change last month.
"This raises questions regarding damage and responsibility in national jurisdictions, and thus climate justice."