On Dec. 12, 2015, 195 countries gathered in the French capital to conclude the world's first universal climate treaty, the Paris Agreement, aimed at preventing worst-case scenarios for global warming.
The Palestinian authorities have since also signed the pact, which has been officially ratified by 144 parties and entered into force in record time last November.
Here are the key points in the Paris Agreement:
Nations agreed to hold global warming to "well below" two degrees Celsius (3.6 degrees Fahrenheit) over pre-Industrial Revolution levels, and to strive for 1.5 degrees Celsius.
The lower goal was a demand of poor countries and island states at high risk of climate change effects such as rising sea levels.
But experts say even the two-degree cap will be a tough task, requiring an immediate and deep reduction in planet-warming emissions from burning coal, oil and natural gas.
Based on voluntary emissions cuts pledged by countries so far, the planet is on track for warming of about three degrees, many scientists say—a recipe for possibly catastrophic floods, storms, drought and ocean rise.
The signatories will aim for emissions to peak "as soon as possible", with "rapid reductions" thereafter.
By the second half of this century, according to the pact, there must be a balance between emissions from human activities such as energy production and farming, and the amount that can be absorbed by carbon-absorbing "sinks" such as forests or storage technology.
Developed countries, which have polluted for longer, must take the lead with absolute emissions cuts.
Developing nations, which still burn coal and oil to power growing populations and economies, are encouraged to "continue enhancing" their efforts and "move over time" towards cuts.
In 2018, and every five years thereafter, countries will take stock of the overall impact of their efforts to rein in global warming, according to the text.
It "urges" and "requests" countries to update their pledges by 2020.
Some nations have set emissions-curbing targets for 2025, others for 2030. Both categories will be updated every five years.
Rich countries are expected to provide funding to help developing countries make the costly shift to cleaner energy sources and shore up defences against the impacts of climate change.
Donor nations must report every two years on their financing levels—current and intended.
In a nonbinding "decision" that accompanies the agreement but is not included in it, the $100 billion (91 billion euros) per year that rich countries have pledged to muster by 2020 is referred to as a "floor"—meaning it can only go up.
The amount must be updated by 2025.
Pledges made in 2015 alone would boost public financing (excluding private money) to $67 billion in 2020, according to an OECD report.
Rich nations blamed for their longer contribution to carbon pollution balked at the idea of financial compensation for countries suffering the consequences of climate change.
But the agreement does recognise the need for "averting, minimising and addressing" losses suffered.
Explore further: Highlights of the proposed UN climate accord