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Explainer: Paris Agreement on climate change to ‘enter into force’

Posted on 12 October 2016 by Guest Author

This is a re-post from Carbon Brief by Sophie Yeo

The Paris Agreement will formally come into force next month, legally binding countries that have ratified the deal to act on the pledges made last year.

This includes a commitment by every country to prepare increasingly ambitious pledges to tackle greenhouse gas emissions every five years, known as Nationally Determined Contributions.

There were two thresholds that had to be crossed before the deal could come into force: at least 55 countries covering at least 55% of global emissions had to ratify the deal.

The first of these thresholds was passed on 21 September. As of today, 74 countries have ratified the deal. The EU’s fast-tracked ratification, which concluded on 4 October with the European Parliament’s vote in favour, has now pushed the deal over the second threshold.

The deal won’t come into force instantly. The Paris Agreement stipulates that this will happen 30 days after both the thresholds have been crossed. The UN says this will be on 4 November.

But it does mean that it will be in force before countries meet again for their first major UN climate meeting since Paris — and before the US elections on the 8 November.

Unexpected haste

By all accounts, countries have acted with remarkable haste in ratifying the Paris Agreement.

A raft of countries ratified the deal on 22 April, which was the first possible opportunity to do so. These mainly included small island states, whose emissions are negligible in the context of global emissions.

While these early-ratifying small countries helped to inch the agreement towards the first threshold, it was important to bring the big emitters on board to reach the second threshold.

On 3 September, the US and China jointly ratified the agreement. Together they were responsible for 38% of global emissions. This provided a big boost, but not quite enough to tip the total beyond 55%.

For a short time, there was a question mark over how the remainder would be made up, with doubts clouding the will or ability of the remaining big emitters to ratify.

India, responsible for 4% of emissions, had opposed the inclusion of a ratification deadline in the G20 communique in September. The EU, whose member states make up 12% of emissions, was widely considered to have too many bureaucratic mountains to scale to make speedy ratification a reality. Russia, responsible for 8% of emissions, has said it will not fast-track ratification to simply to catch up with other nations that have already ratified.

Russia kept to its word and has not yet ratified the agreement. But India ratified on 2 October and the EU managed to fast-track its ratification, allowing the emissions of the member states which had already ratified domestically — France, Hungary, Austria, Germany, Slovakia, Portugal and Malta — to be counted towards the 55% total.

One quirk of the Paris Agreement is that the percentages of global emissions assigned to each country are not based on the most up-to-date statistics available, but rather the most recent data that each country has provided to the UN.

In some cases, there is a significant disparity between what the country has reported and what percentage of emissions it is responsible for today.

According to the Global Carbon Project, China was responsible for 27% of global emissions in 2014, compared to the 20% that it submitted to the UN in 2005 and was counted for the purpose of its ratification. Similarly, the US was responsible for 15% of global emissions, rather than the 18% counted towards ratification.

Based on the latest data, these two countries combined are responsible for 42% of global emissions, which would have eased the burden of crossing the 55% threshold by 4% compared to the earlier shares that were actually counted.

What does this mean?

The entry into force of the Paris Agreement has a number of important implications.

It means that many of the provisions set out in December will now become legally binding on nations that have ratified. This includes drawing up plans to tackle climate change and providing financial and technical support to developing countries. They will also have to undertake appropriate adaptation actions. Carbon Brief has an interactive graphic setting out the full details of the final deal.

Countries cannot withdraw from the agreement for three years following its entry into force. If a country decides to exit after this time has expired, they need to wait another year before they can formally leave.

In light of the US elections, this is an important provision. Republican candidate Donald Trump has pledged to withdraw the US from the Paris Agreement if he becomes president.

Entry into force means that, even if he withdrew from the Agreement on his first day in office, the US wouldn’t actually leave for another four years. Unless Trump won a second term, there would be another president in office when this took effect.


The rapid entry into force also causes something of a logistical headache.

No one expected the Paris Agreement to come into force as early as it did. Until the penultimate draft of the Paris text, there were no options to allow the deal to come into force before 2020.

While the Paris Agreement set the direction for future climate action, its guiding rulebook still needs to be developed. In particular, a huge workload has been assigned to the “Ad Hoc Working Group on the Paris Agreement” (APA), which was set up to prepare the deal for entry into force.

The deadline for these tasks is the first meeting at which the Paris Agreement is in force, by which time the group is meant to have completed the rulebook. The APA started discussing these issues in May but, thanks to the deal’s unexpectedly speedy ratification, this work is still unfinished.

Once the Paris Agreement goes into force, discussions technically start taking place under the “Conference of the Parties serving as the meeting of the Parties to the Paris Agreement” (CMA). Thanks to the early entry into force, this will now take place for the first time in Marrakech in November, which is known as COP22.

The problem is that only countries that have ratified the agreement can take part in these discussions. This has left many countries concerned that they’ll be left out of important future discussions on the technical side of the Paris Agreement.

The French and Moroccan presidencies have released a document aiming to ease these worries.

One option, they say, is to immediately suspend the CMA and continue working on the rulebook in Marrakech as though the agreement hasn’t come into force — that is to say, with the inclusion of all countries, whether they have ratified or not. The World Resources Institute, a think-tank based in Washington DC, has detailed information about the options available and how they could work.

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Comments 1 to 14:

  1. I am confused about the statement, "On 3 September, the US and China jointly ratified the agreement.".  I remember this in the news.  However, how can Obama claim ratification without the approval of congress?  Is the USA claiming to be one of the countries ratifying?  Most people believe any climate deal could not be passed in Republican controled Congress.  

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  2. This article about policy decisions of countries is anthropocentric blathering at the highest level! The stark reality is that the best that can be done by reducing the global rate of greenhouse gas emissions as quickly as is physically possible is to slow down the irreversible rapid climate change and ocean acidification and warming. What is really needed is a global focus on measures to cope with such consequences as sea level rise.

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  3. Why do you believe that we have "irreversible rapid climate change" even if world manages to reduce CO2 emissions? There is committed warming obviously, but irreversable? Reduce the CO2 in atmosphere and temperatures will drop.

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  4. ELIofVA

    The Paris AGreement is under the auspices of the The United Nations Framework Convention on Climate Change (UNFCCC)

    "The United Nations Framework Convention on Climate Change (UNFCCC) is an international environmental treaty negotiated at the Earth Summit in Rio de Janeiro from 3 to 14 June 1992, then entered into force on 21 March 1994."

    The US is a signatory to the convention, so it has already signed and ratified that threaty long ago. That step required Congress. Now agreements entered into within the treaty aren't then regarded as new treaties, but simply part of an existing treaty. My understanding is that under US law that does not require Congress.

    Additionally the national targets are intentions, not strictly binding; there is no enforcement mechanism.

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  5. RE: #3: scaddenp, there are some, like Guy McPherson, who believe we have already passed "a point of no return" and face extinction. Others, like Kevin Anderson, think we are very late in the game here, but, perhaps, still can avert the most dire consequences of climate change if we take immediate and appropriate action. In videos and papers, he does make suggestions.

    I am not a scientist, but there does seem to be some validity to the idea that climate change may, at this time, be irreversible.

    Please correct me if I am wrong.

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  6. I don't think McPherson's claims are based on published science. There have been studies of this, and you might like to look at this post on climate commitments though I suspect there may be more recent work.

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  7. @raindog,

     There is a lot of potential for McPherson to be right. However, having watched several of his lectures, the one glaring gap that he certainly overlooks is humanity's ability to affect stabilizing feedbacks. He is correct in so much as right now almost all those human influenced stabilizing feedbacks are degraded as a continuing result of our influence.

    However we do have an equally large potential for positively affecting them. In other words, humans have equal ability to restore ecosystem function as degrade ecosystem function. Humans are just as capable of planting a forest as slash and burning a forest. We are just as capable of creating a wetland as draining one. We can as easily restore a savana or prairie as plow it and plant corn. We just don't happen to be by and large doing it at the moment. In fact we have to spend lots more effort, money and energy keeping those ecosystems non-functional as we would have to spend to restore those ecosystem functions.

    "We try to grow things that want to die, and kill things that want to live. That is pretty much how (industrial) agriculture functions." Colin Seis

    In my honest opinion McPherson could be right, but it is not necessarily a given. There is no requirement that humans interact with the biosphere the way we ciurrently do now. But I also believe he is correct, conditional to if we don't radically and fundamentally change that interaction.

    That would include a 3 way approach, reducing fossil fuels, Biological Carbon Capture and Storage (BCCS) in agriculture, and large scale ecosystem recovery projects. The more I study it, the more I am convinced it can work, but would require all 3. I am almost certain that focusing only on fossil fuel emissions will ultimately fail due to exactly what McPherson talks about in his lectures. Too much much CO2 in the atmosphere already, and too much heating already stored in the system, taking too long to get rid of without humanity making a concious and real effort to help instead of hinder recovery.

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  8. scaddenp#6 I think that there is significant consensis among researchers (and, perhaps, even policy makers — "By all accounts, countries have acted with remarkable haste in ratifying the Paris Agreement") that, even if we are able to limit warming to 2°C (which seems unlikely), we have already triggered significant "positive feedback" conditions (such as Arctic melting, releases of methane, acidification of the ocean, extinction of other species, etc.) that will contribute to climate change in a sort of snowball effect that cannot be controlled or reversed.

    [Gavin Schmidt, director of Nasa’s Goddard Institute for Space Studies]... is the highest-profile scientist to effectively write-off the 1.5C target, which was adopted at December’s UN summit after heavy lobbying from island nations that risk being inundated by rising seas if temperatures exceed this level. Recent research found that just five more years of carbon dioxide emissions at current levels will virtually wipe out any chance of restraining temperatures to a 1.5C increase and avoid runaway climate change. (

    It seems that even a commitment to 2°C may be too little, too late (as it appears is already the case for some small island & low-lying nations already suffering effects of sea-level rise, for example).

    I understand the "irreversible", in this context, to mean something similar to "cannot be controlled by human efforts" (e.g., geo-engineering).

    Perhaps we should just talk about it for another 5 years and see what happens ... ?


    no dapl

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  9. RedBaron #7 I agree with you, and with the combination of your 3 approaches.

    What I see is a lack of will to actually take the actions necessary, on the scale and within the time required, among the folks who would make the difference (roughly those earmarked by Anderson).

    no-dapl ... leave it in the ground

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  10. raindog, in March, 2009 Michael Tobis sketched a schematic graph of the distribution of scientific opinion on the consequences of Business As Usual emissions.  In January, 2010, he published this cleaned up version:

    The important point for your discussion @5 and @8 is that the official consensus position, ie, that of the IPCC is for "substantial cost" and that views of iminent catastrophe are to be found among a minority of climate scientists.  Views of imminent extinction are so rare among climate scientists as to not even make it on the chart.  Since 2010, evidence has tended to show the long tail of climate sensitivity (and hence the probability of extreme upper range temperature predictions) have reduced, which would if anything, compress the right hand side of the above distribution.

    For more exact information on the distribution of scientific opinion, we must turn to von Storch and Bray's series of surveys of climate scientists (which despite what I identify as biases from the authors being reflected in the wording of some of the questions, remains the best available).  Their most recent survey includes among many others, the following question:

    Figure 88. (v043) How convinced are you that climate change poses a very serious and
    dangerous threat to humanity? 

    Possible responses were on a scale, showing "not at all 1 2 3 4 5 6 7 very much".  The responses, in order and reported as a percentage, were 2.194, 3.108, 3.291, 5.667, 13.53, 26.14, and 46.07.  That indicates the majority scientific opinion is that climate change poses a very serious and dangerous threat, but that falls far short of an exinction level threat (which unfortunately it was not possible to indicate).  That less than 50% are "very much" convinced of the possibility of a "very serious and dangerous threat", however, shows it to be very unlikely that many (if any) are convinced it is an extinction level threat.

    More specifically to your points, the consensus on Arctic Sea Ice is that it has no tipping point, so that even if completely removed, it would rapidly return of Arctic SSTs were Arctic tempertures dropped to normal values (ie, 1960s values).  On methane, the majority opinion among relevant scientists is that there is no "clathrate bomb".  And so on.  There are some credible "runaway processes" but they will, as yet, have minimal overall impact.

    With regard to your specific quote @8, the threat of "runaway climate change", contrary to appearences, was raised neither by Gavin Schmidt nor the "recent research".  It is introduced without basis by the author, and passed of as being on the authority of Schmidt and/or the research in a dishonest fashion.  The article proves mostly that there is now a niche in more left leaning media, and on some blogs, for authors who want to feed a diet of pure catastrophism which is unjustified by the scientific consensus.

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  11. Raindog - Gavin gets pretty exaseperated by misrepresentation of his point of view. See his response at Realclimate on similar point.

    "I understand the "irreversible", in this context, to mean something similar to "cannot be controlled by human efforts" (e.g., geo-engineering)."

    I think that the papers I pointed to earlier would suggest that we are committed to 2degree warming. However, I dont see evidence let alone consensus for any warming that is not reversible by simply stopping emitting CO2. I dont think that is even  geoengineering.

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  12. Tom Curtis #10 Thank you very much for the clarification/correction. I see that it is very easy for someone new to this discussion to go astray. 

    I would only add that this situation is already somewhat of a catastrophe for some of us ( as I watch the current king tide bring the sea to within 10' of my back door and see corals dead or dying everywhere ...).

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  13. scaddenp #11 Yes, I can see why Gavin might be exasperated.

    I understand the "committment"; I think there are reasons to doubt that it will/can be carried out (as I indicated above #9). And, if not, then :

    Many aspects of climate change and associated impacts will continue for centuries, even if anthropogenic emissions of greenhouse gases are stopped. The risks of abrupt or irreversible changes increase as the magnitude of the warming increases. {2.4}

    [Climate Change 2014 Synthesis Report, IPCC]

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  14. Tom Curtis #10 I am a bit concerned about the interpretation of "very serious and dangerous threat to humanity". It appears to me that the phrase could mean many things and different things to different people. The survey is indeterminate in this respect. As it stands, it is not clear to me that it excludes the possibility of extinction. Does this phrase have some more or less standard meaning in science?

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