After years of wrangling, a new climate change deal was finally agreed on 12 December. The Paris Agreement, approved by 195 countries, has been hailed as the most important environmental treaty to date but the hard work of reining in carbon emissions is still to come.

Here are the key details of what’s been agreed:

What’s the aim of the agreement?

The agreement aims to keep the rise in worldwide average temperatures below 2°C, compared with pre-industrial levels, and pursue efforts to limit the increase to 1.5°C. Considering the global mean temperature has already risen by about 0.85°C, a big reduction in greenhouse gas emissions will be required.

How will reductions be achieved?

Unlike the earlier Kyoto Protocol, which required a detailed plan and specific emissions goals from each country (and failed at reducing global CO2 emissions), the Paris Agreement provides a framework to encourage countries to make cuts to their emissions, without legally requiring any reductions.

Instead, each country submits an “Intended Nationally Determined Contribution” (INDC) pledge to reduce its emissions, which takes into account national circumstances and level of development.

Who’s doing what?

Every major greenhouse gas-emitting country has submitted a pledge to the UN over the past two years. But an assessment of these pledges concluded that even if all these countries met their targets, the average global temperature would still increase to at least 2.7°C above pre-industrial levels by 2100.

The Paris Agreement requires each country to review its progress and reassess targets every five years from 2020. The idea is countries will ratchet up their commitment to reducing emissions in the next few decades.

So there’s a long way to go, with the world’s biggest emitters needing to drastically, and quickly, reduce the amount of greenhouse gases they emit.

In 2013, the Intergovernmental Panel on Climate Change published a “carbon budget”, showing how much the world can emit and still have a decent shot at staying below 2°C warming. According to an analysis by PwC, the world’s current rate of emissions means this budget will be exhausted within 20 years.

Will developing countries get help?

The agreement requires wealthy countries to help developing countries adopt renewable energy and cope with the impacts of climate change. But it stops short of providing a basis for any “liability or compensation”, so developed countries won’t be required to pay reparations to those affected by sea level rise or extreme weather events.

What is New Zealand doing?

Our INDC, submitted earlier this year, pledges to reduce greenhouse gas emissions to 30 percent below 2005 levels by 2030. But the document is vague on how we’ll achieve this. Agriculture is our biggest single contributor to greenhouse gas emissions (48 percent), and the pledge said New Zealand is “taking serious action” by funding “research into technology to reduce agricultural greenhouse gas emissions”. However, this doesn’t extend to a concrete plan to cut emissions from farming.

Energy use represents 39 percent of our emissions, of which 17 percent is from transport. The INDC is even less specific on how this will be reduced, stating “in principle, New Zealand is well-placed to take advantage of its existing […] renewable sources of electricity”, and the government “will further support transformation of our transport sector”.

Massey University Centre for Energy Research director Professor Ralph Sims, who was at the conference, said the Paris Agreement is “in many ways a compromise”, and doubts it will have any immediate impacts on government policies.

One step the government has taken was to announce a review of the Emissions Trading Scheme (ETS) in the month leading up to the Paris Conference, to assess how the scheme could be modified to meet these tougher emissions targets. The ETS has been criticised as an inadequate tool to combat climate change. For example, according to a recent Stockholm Environment Institute study, 55% of carbon credits purchased under our ETS – one carbon credit should represent one tonne of reduced greenhouse gas emissions – originated from Russia and Ukraine. However, these credits aren’t linked to any real greenhouse gas reductions.

Professor Sims, who chairs the Royal Society’s Climate Change Mitigation Panel, says the panel will advise the government “there is much New Zealand can do to reduce our GHG [greenhouse gas] emissions”. He also thinks New Zealand should move away from “buying carbon credits from offshore, as is the current intention”.

by George Block