What is the significance of the Paris climate talks?

In 30 years, carbon dioxide levels in the atmosphere will have risen to such an extent that temperatures will be 2C higher than in pre-industrial times, scientists say. Beyond that temperature, there will be devastating environmental consequences: worsening storms, extreme heat waves and rising seas. The most important decision to be taken in Paris will therefore be to agree, through a binding commitment, that 2C is the highest acceptable limit of global warming on Earth. All other decisions taken in Paris will follow as a consequence of that agreement.

What are the problems that lie ahead for delegates in making that commitment work?

To keep any temperature rise to a 2C limit, delegates will have to call for pledges from countries and power blocks (such as the European Union) and then settle individual targets. That will be extremely tricky. In addition, once particular cuts have been agreed in carbon outputs, a commission will have to be set up to monitor nations’ emissions in order to check that they are keeping to their pledges.

What will be the cost?

The high levels of carbon dioxide in the atmosphere today are the handiwork of the industrialised developed nations. Developing countries will therefore demand a clear commitment from them to provide financial support to help them to adapt to a hotter planet and to militate against the worst effects of global warming. By 2020, the amount of money needed for this purpose is expected to be around $100bn a year. Pledges to reach such a funding level will be another key milestone that will have to be reached in Paris.

What other issues will have to be faced?

Some nations face more than damaging impacts from global warming They can foresee complete devastation. Large tracts of Bangladesh coastline, the Maldives and some Pacific archipelagos face inundation, for example. Some form of compensation for populations who could lose their homelands will therefore need particular attention and a mechanism will have to be agreed in Paris to ensure that these people are properly recompensed for future generations. In addition, new forms of tide, wave and wind power plants will have to be developed to replace generators that rely on fossil fuels. A method to allow systems created in one country to be shared with other countries in an equitable manner will have to be agreed to ensure the rapid take-up of technologies that will be crucial to efforts to keep global warming within bearable limits.

Will the pope’s intervention make a difference?

At times the debate over climate change has suffered from being forbiddingly technical and arcane. A high-profile and impassioned intervention by a popular pope, who has already managed to win admiration from non-Catholics as well as inside the church, is bound to focus minds ahead of Paris.