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Why 50x30 ?

A large majority of countries now have pledged carbon neutrality or “net zero” emissions by 2050, and also adopted the Paris Agreement goal of holding warming under 2°C, and as close as possible to 1.5°C. The IPCC Special Report on 1.5°C of Warming (2018) however made clear that 45-60% emissions reductions (median 50%) are needed by 2030 to reach carbon neutrality by 2050, and remain close to 1.5°C of warming.


Unfortunately, the UNFCCC Synthesis Report, released on February 26, 2021 made clear that almost no countries are taking their 2050 neutrality goals seriously by taking the needed steps to get there through 50% reductions by 2030. Instead, current national measures will only reduce global emissions by about 1% by 2030.


The result will be “overshoot” – exceeding not only the 1.5°C limit, but also the 2°C Paris Agreement. Indeed, current pledges will hold the planet to just below 3°C of warming – and that, only if all existing pledges actually are implemented. The reality however is that global carbon emissions continue to grow, not decline. Our current emissions pathway will bring us to 2°C of warming already by 2050, and over 4°C by 2100, with carbon dioxide levels above 600ppm for the first time in 3 million years.


The de facto decision by today’s governments to pursue overshoot carbon policies – and they should be honestly recognized as a conscious decision, not an inevitability -- will have permanent and essentially irreversible impacts in the world’s cryosphere – snow and ice regions – as well as polar and near-polar oceans, with cold waters that acidify more rapidly. Cryosphere not only helps cool and regulate the climate system, but also holds much of the world’s fresh water resources. Once this ice melts however, or polar oceans acidify beyond the ability to support life, a return to lower temperatures and CO2 levels will not reverse many of these changes.


New research shows that our polar ice sheets, especially Antarctica will continue to lose ice and raise sea levels for many thousands of years, even after a return to lower temperatures. Glaciers, once lost, can re-grow; but only over many hundreds of years. Permafrost, once thawed continues to emit carbon for 1-2 centuries – meaning that overshoot will commit five-six generations of humans to some sort of carbon dioxide removal even once human carbon neutrality is reached, just to compensate for permafrost carbon emissions. Even Arctic sea ice will take at least several decades or a century to return, because the Arctic Ocean will remain warmer for centuries even after air temperatures decline.


The more rapid acidification of polar oceans and seas, forming the world’s richest fisheries is perhaps the most irreversible: taking 50-70,000 years to return to today’s levels. The shell-building animals at the base of the ocean food chain will go extinct; and with them, fish and animals on which they depend. Already today, at 1.2°C of warming and about 415ppm CO2, extensive damage to shellbuilding organisms has been documented by researchers in both polar regions.


The consequences from overshoot are dangerously underestimated by the policy world. While there are other near-irreversible impacts from exceeding 1.5° or 2°C, especially loss of coral reefs and a potential loss of the Amazon ecosystem, those from cryosphere stand out in their semi-permanent nature and global impacts. Massive unstoppable sea-level rise of 5-20 meters in just a few centuries. Loss of water resources reliant on glaciers and snowpack. Decline and extinction of cold-water species, including commercially important stocks of cod, salmon, lobster and shellfish. With overshoot, we also face greater reliance on untried carbon dioxide removal (CDR) methods; and potential trade-offs with food, biodiversity and other Sustainable Development Goals.


While on paper declaring “planetary emergencies” and committing to carbon neutrality, very few governments and businesses are responding to IPCC science. In particular, far too many are using questionable accounting methods that do not reflect the reality of their resulting emissions: omitting large and important economic sectors; continuing to build and export fossil fuel industries with high carbon emissions; and in general not putting their pledges on neutrality into national policies and actions.


It is important to stress that there are exceptions however, including some major industrial economies with “50x30” consistent plans. 50x30 will raise these up as concrete examples of both the possible, and the necessary, in the lead-up to COP-26 in Glasgow where 2030 climate commitments will be finalized. Just as the global scientific community and IPCC make clear the sheer scale of ecosystem loss, damage and human suffering that will result from cryosphere impacts with overshoot; scientists are equally clear that the window for 50x30 action has not yet closed. With political and economic will, we can still prevent this.


The cryosphere will not care where the carbon emissions causing higher temperatures and acidification rates arise. It will simply respond, as it always has, to the chemical reality of CO2 meeting cold water; and to the physical reality of the melting point of ice.


The need for 50x30 is a scientific reality for cryosphere and climate researchers, who see the window for sufficient action closing. If your research institution, university department or non-governmental organization wishes to endorse the 50x30 Mission Statement, please see How to Join or contact; and we will add your organization and logo to the 50x30 webpage; as well as provide educational materials and opportunities for additional outreach, if desired.


If you represent a business or institution with concrete plans to meet the 50x30 benchmark, please contact

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