An analysis has found that delaying emissions cuts by just 5-10 years sharply raises the probability that Atlantic ocean circulation will cross a tipping point and collapse. A research team led by Professor Kook Jong-seong of the School of Earth and Environmental Sciences at Seoul National University produced findings that even if climate mitigation succeeds in stabilizing carbon dioxide concentrations, this circulation does not necessarily follow a recovery path. Even under identical or similar carbon concentration conditions, the path diverged between recovery and collapse lasting several centuries depending on the simulation. The point is that how quickly the target is reached matters as much as setting the target year.
The Atlantic Meridional Overturning Circulation (AMOC) carries heat and salt from the equator to high latitudes, regulating the global climate. It is also classified as a leading tipping point of climate change. The research team explained that once the circulation reaches a state near its tipping point, small stochastic fluctuations in the atmosphere can accumulate and push it toward collapse. Internal patterns such as high-pressure anomalies that linger over the North Atlantic can act as a trigger.
The IPCC's assessment has a somewhat different tone. While it considers it very likely that this circulation will weaken during the 21st century, it views an abrupt collapse before 2100 as unlikely. Rather than the two assessments being in direct conflict, this is closer to a new layer of results that look into the world after mitigation succeeds.
The term carbon neutrality itself also needs to be read precisely. The IPCC defines it as a state in which anthropogenic carbon dioxide emissions and anthropogenic removals are balanced over a given period. It does not mean emissions become zero, nor that warming stops at that point. To halt temperature rise, global emissions must approach zero, and even with a sharp drop in emissions, temperatures can rise and fall in the short term because of natural atmospheric and oceanic variability and non-CO2 greenhouse gases such as methane.
The ocean moves on a longer timetable. Heat accumulated in the ocean is released over decades to centuries, and even if warming is limited, some changes such as sea level rise can continue for more than several centuries. This is why it is hard to feel reassured by a single arrival point of 2050.
As it happens, the domestic policy clock faces the same question. On the 3rd, the National Assembly's Special Committee on the Climate Crisis held the first meeting of a public deliberation committee to set a long-term carbon neutrality reduction pathway. The plan is to decide the 2036-2049 greenhouse gas reduction plan through public deliberation. On the same day, the National Assembly Research Service also issued a report on the need for National Assembly climate deliberation to support legislative discussion of a carbon reduction pathway.
The starting point was the Constitutional Court's ruling of constitutional nonconformity in August 2024. The reason was that Article 8, Paragraph 1 of the Carbon Neutrality Framework Act presents plans only through 2030 and does not include reduction plans for 2031-2049. The same law stipulates zero carbon emissions in 2050. The destination was written down while the road there was left blank.
The public deliberation committee will be made up of some ten members, including Rep. Park Ji-hye of the Democratic Party of Korea and Rep. Kim So-hee of the People Power Party, the ruling and opposition secretaries of the climate committee, along with deliberation experts, plus a citizen panel of 500. The plan is to prepare an amendment to the Carbon Neutrality Act by the end of March. The revision deadline set by the Constitutional Court is the 28th of this month, but the deadline is expected to be missed as the establishment of the 2035 NDC has been delayed. The 2035 NDC finalized last November calls for a 53-61% reduction from 2018 levels.
There are precedents to consult. Shortly after legislating its carbon neutrality target, the UK House of Commons formed a climate assembly of 108 citizens, which produced recommendations through six weekend sessions over four months, and those contents were reflected in actual carbon neutrality policy. In Germany, a climate assembly led by civic groups was held 12 times over two months with 160 participants.
The numbers of participants and the durations differed, but the common thread is clear. The outcomes of deliberation were carried over into the language of laws and policies.
The message the research delivers is a question of timetable. It is not a forecast of catastrophe. If a delay of 5-10 years greatly changes the probability, then what slope is drawn into the 2036-2049 stretch carries as much weight as the target year. How tipping point risk will be reflected in pathway design remains to be discussed.
Who will be part of the citizen panel of 500 is being decided from now on. It is worth taking a look at the public deliberation schedule and the participant recruitment notice from the National Assembly's Special Committee on the Climate Crisis. One of the 500 who will directly decide how fast reductions proceed after 2036 could be the person reading this.
