NEW DELHI: Over 150 world leaders are in Paris for Day 1 of the historic climate talks, hoping to arrive at a treaty that will force countries to curb their carbon emissions. The COP21, or the 21st Conference of the Parties to the United Nations Framework Convention on Climate Change, is on till December 11, and is widely being seen as the last chance for countries to agree on how to tackle climate change, as negotiators in 2011 had fixed 2015 as the year to have this deal done and signed.

The talks, as is evident from the above, are extremely important, which is why The Citizen has put together a cheat sheet for our readers. Here’s everything you need to know about COP21:

What are the talks trying to achieve?

The talks, as mentioned above, aim to arrive at a global climate treaty. Countries have already committed to curbing human activities that contribute to climate change, but there is no consensus on how to deal with the issue.

The need to arrive at a consensus is of pressing concern, as the world has crossed the halfway mark of warming about 2°C above pre-industrial times -- at which point there will be dangerous and unpredictable impacts on our climate system.

One of the major bottlenecks in the emergence of a consensus is the question on how to enable developing countries to grow as well as limit emissions. Countries like China and India -- two of three largest carbon emitters in the world -- have been resistant to a climate treaty as they feel that a majority of damage was caused by the rapid industrialisation of the developed world, and that they shouldn’t be made to share the burden in cutting emissions where their economies are seeing an upswing in growth. The developed world, they feel, has had unrestricted use of fossil fuels for 200 years -- enabling its growth, and now they shouldn’t be made to pay for that use.

The Paris summit, therefore, will have to strike a balance on cutting emissions from fossil fuels as well as on the right to use them.

Further, another key question for deliberation is: who will pay? If the world expects a move toward renewable energy, such as solar and wind power, as well as the adoption of more efficient technology -- can poor nations be expected to fork the bill? Or should the richer nations pay for the transition of the poorer countries, and if so, how will these payments be worked out and structured, and who will pay what?

Other matters of deliberation concern the countries worst affected -- mostly small island nations. Can these countries, which will be faced with the impact of rising temperatures in the form of submergence, sue richer countries for causing the problem in the first place?

The developed world, however, maintains that the divide between rich and poor is not what it used to be. The world has changed since the UNFCCC started back in 1992, back when the world was divided based on income. Today, there is a need for all countries to shoulder the responsibility for climate change -- as all are going to be affected by it. Emissions last year were the highest ever.

Is a deal likely?

It’s difficult to say, but a deal that comprehensively addresses all the above issues is quite unlikely. At best, we will see a compromise deal that touches on some of the concerns relating to climate change, but at this point, something is better than nothing.

Further, even if a deal was arrived at and agreed to, there could be challenges stemming from the ratification of that deal in individual countries. Take the example of the US, which in 1997 signed the Kyoto Protocol after a climate conference in Japan. The US Congress refused to ratify the agreement, causing the US to pull out. Several other countries followed suit, leaving the Kyoto Protocol ineffective.

If a treaty is arrived at in Paris, it will not be legally binding on the US, and is therefore more of an "executive agreement" under American law, meaning it will not need to be submitted for the advice and consent of the Senate. In a sign of things to come, Republican lawmakers threatened just before the summit to withhold $500 million that Obama had pledged to a UN fund for developing nations adapt to climate change and reduce their emissions, insisting that the president must promise to get approval for any climate agreement from the Senate.

Who all are attending and when is the COP21?

The summit is being attended by over 150 world leaders, and a total of about 40,000 people including government officials, lobbyists, industrialists, and others. The talks are on for two weeks: November 30 to December 11.

What is climate change?

Earth’s climate is constantly changing. The global average temperature today is about 15C -- but it has been much higher or lower in the past. The problem today, however, is that the rapid change in temperature isn’t caused by natural patterns, but human-led industrialisation that is causing the planet to heat up. Scientists are therefore concerned that the natural fluctuation, or variability, is being overtaken by a rapid human-induced warming -- which will have serious consequences on the planet’s climate.

This warming of the planet is known as the greenhouse effect. Greenhouse gas emissions include carbon dioxide (from fossil fuels, deforestation, biomass), methane, nitrous oxide, and fluorinated gasses. The greenhouse effect is caused by the fact that the earth's atmosphere traps some of the energy from the Sun. Solar energy then radiating back out to space from the earth's surface is absorbed by atmospheric greenhouse gases and re-emitted in all directions. The energy that radiates back down to the planet causes heating of both the lower atmosphere and the earth’s surface.

Now this process is actually beneficial to life, keeping the earth warm enough for organisms to thrive. The problem is that with excess emissions, we are causing an increase in the greenhouse effect. Emissions from industry and human activity in general is adding to the already present greenhouse gases and causing rapid and artificial heating of the earth’s surface and lower atmosphere.

What is the proof?

Here are some graphs from the ‘ Summary for Policymakers‘ (SPM) report released by the Intergovernmental Panel on Climate Change (IPCC) and put together by Carbon Brief.

The amount of CO2 in the atmosphere is rising:

The earth’s surface is warming:

Arctic sea ice is melting:

Earth’s surface will continue warming (to dangerous levels):

Sea levels will rise (to dangerous levels):

Rainfall patterns will change: