Key questions on the Paris agreement

lWhat is the Paris Agreement? At United Nations talks in Paris last December, the world’s first comprehensive climate deal was produced. The Paris Agreement will see action to curb rising temperatures by all countries.

lHow many countries have signed up? There are 180 signatories to the Paris Agreement but, until today, just 24 states had ratified the deal — accounting for 1.08pc of the total global greenhouse gas emissions. The move by China and the US bolsters the agreement — bringing the total greenhouse gas emissions accounted for by signatories to 39.06pc.

lWhy do countries need to “ratify” the deal? For the agreement to come into force, at least 55 countries, representing 55pc of the world’s climate emissions, must ratify the deal to drive down greenhouse gases. In doing so, they make the agreement legally binding.

lHas Ireland ratified the deal? Not yet, but last April — before our change of government — then environment minister Alan Kelly signed the deal, saying he hoped Ireland would ratify the Paris Agreement later this year or early next year, in line with pledges made in the EU. Denis Naughten is the current Minister for of Communications, Climate Action and Environment.

lWe’ve known about climate change for decades, why are we only doing this now? This deal has effectively been 20 years in the making. A first treaty, the Kyoto Protocol — which was adopted in 1997, only covered the emissions of developed countries — and the US never ratified it. It runs out in 2020 and the Paris Agreement will be its successor.

Have any previous environmental treaties actually worked? Yes, though not for as wide-ranging an issue as climate change. The Montreal Protocol, for example, agreed in 1987 and ratified by all UN countries, has been successful in phasing out use of the chemicals which cause the ozone layer to be depleted.