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ORIGINAL FRENCH ARTICLE: https://www.humanite.fr/climat-ne-p...

by Marie-Noëlle Bertrand, Alexandra Chaignon, Eric Serres


Translated Sunday 21 October 2018, by Meghan O’Shea

The special report by the Intergovernmental Panel on Climate Change (IPCC), which was approved Saturday by the 195 member states, concludes that the goal can be met, provided our systems of production are radically and rapidly transformed.

A number of the conclusions had been anticipated, and yet, in its entirety it was still unexpected: adopted Saturday by the 195 UN’s member states, the IPCC’s special report "Global Warming of 1.5 °C" was publicly released last night. At a time when the topic of climate change has usually left the world feeling despondent, the findings of this new scientific analysis have led to the reverse: yes, says the Intergovernmental Panel on Climate Change, it is still possible to limit the temperature increase to 1.5 °C, compared to the averages recorded before 1900 and the industrial era. But we must act quickly and take radical measures, argue the authors of the report, which also specifies why it is vital to do so.

1. 1.5°C, which is essential for all, and vital for the South
To limit the global temperature by 1.5°C or 2°C? This issue has been openly discussed for several years, the halfway mark appearing in the Paris agreement, which was adopted by the COP21, in 2015. This difference of a few tenths of a degree can seem minimal. However, it is essential. In short, letting the Earth warm by 2 °C would also allow for slightly greater greenhouse gas emissions than 1.5 °C, thereby requiring less effort from the countries that pollute the most. On the other hand, such an increase in temperatures would cause more overall damage, especially to the countries in the Global South, which are extremely vulnerable to the effects of climate change.

The Fifth IPCC report on climate change, published in 2013 and 2014, already listed the scientific likelihoods concerning this problem. But the data was considered limited and lacked precision, giving the most stubborn states a loophole and allowing them to make the most minimal of efforts. This special report commissioned by the UN’s IPCC shortly after the adoption of the Paris agreement fills in the gaps, and provides a detailed review of what separates a world with an increase of 1.5°C from a world with an increase of 2°C. It also gives an assessment of the measures that could be taken and sets forth a deadline.

Every tenth of a degree matters.

2. At 2°C, the survival of 99% of the world’s coral will be compromised
The experts at the IPCC are clear: a difference between an increase in global temperature of 1.5°C and 2°C will have significant consequences. Of course, these effects will intensify, according to the magnitude of the warming. Acknowledging that certain situations are, for some, already irreversible... rising sea levels, rising temperatures, increases in droughts and heavy rainfall... the increase in global temperature will undoubtedly bring in its wake an increase in extreme weather events around the world. This comes as no surprise. But experts have fine-tuned their forecasts, believing it to be very likely that "days will be extremely hot in the in mid-latitudes, warming by about 3°C with an overall global warming of 1.5°C or about 4°C with an overall global warming of 2°C".

Another environmental hazard that threatens humanity is rising sea levels. The report projects an average elevation estimated to be between 0.26 and 0.77 meters by 2100, under a 1.5°C increase scenario, and 0.1 meter with an increase in temperatures up to 2°C. Either scenario will inevitably impact the ice sheets. On land, the impact on biodiversity and ecosystems is already well understood. Yet once again, the report is more precise: of the roughly 105,000 species studied, 9.6% of insects, 8% of plants and 4% of vertebrates will see their geographic range cut in half with a warming of 1.5°C; if temperatures were to increase by 2 °C, double the number of species would be impacted.

Any change will also disrupt marine biodiversity and fisheries. The distribution area of many marine species will change. One example is particularly spine-chilling: with an increase of 1.5°C, the amount of coral reef is still expected to decrease by 70 to 90%. With a 2°C increase, the chances are that only 1% will survive, according to the researchers, a change that would impact fisheries and aquaculture. The IPCC predicts a decrease of approximately 1.5 million tons in the annual catch of global fisheries with an increase 1.5°C, and a loss of around twice that if the temperatures increase by 2°C!

Health, food security, water supplies, economic growth... climate-related risks will increase. Some diseases, like malaria or dengue fever will become, once again, widespread, regardless of the increase in temperature. And, as is today, the people most at risk will be the most disadvantaged. However, limiting warming to 1.5°C would reduce the number of people at risk of poverty by several hundred million by 2050. As worrying as all this may be, the IPCC report also offers solutions in the form of possible changes that may be adopted in order to reduce these risks: according to the experts, it is still possible to take action regarding biodiversity management, combating rising sea levels, improving global health and access to food. While warning: "Our ability to adapt has its limits, even with an increase of 1.5°C."

3. 1.5°C is still possible, provided we move quickly...
Unsurprisingly, the report confirms that if we do not change our current methods of production, we will exceed 1.5°C, before we even know it. "It is estimated that human activities have already caused an approximate warming of 1°C (between 0.8 ° C and 1.2 ° C) when compared to the pre-industrial era," say the scientists. They consider it probable (which, in scientific language, corresponds to an important level of certainty) that by continuing at the same rate, the increase of 1.5°C will be reached and exceeded around 2040 (between 2030 and 2052). The effects will be irreversible and persistent for centuries, even millennia. But all is not lost, they also say. While greenhouse gas emissions from the beginning of the industrial era to the present day are already having long-term effects around the world, they are unlikely, on their own, to be sufficient to raise the overall temperature by 1.5°C. In other words, if we can achieve carbon neutrality quickly, or in other words the Earth will be able to absorb as much greenhouse gas as is emitted, we may not exceed - at least not by a lot - this temperature. Of course, as we have said, the effects will linger. But they will be less, compared to an increase in global temperature of 2°C, and their severity will depend on the adaptation measures that will be taken.

4. ... and hit hard
To act quickly, when it comes to greenhouse gases, means drastically reducing the level of emissions. In order to not exceed 1.5°C, the report indicates that they must be reduced by 45 % between 2010 and 2030. And, further along, carbon neutrality must be achieved by 2050. For comparison, to reach the goal of 2°C, a reduction of these same emissions by (only) 20% by 2030 is required, and carbon neutrality must be achieved by 2075. A trajectory which states have failed to grasp. However, we can reach this goal. The transition must be rapid and profound, no matter the sector. Whether it is energy, land use, urban planning and infrastructure (transportation and buildings) or, of course, industrial production. In the face of these challenges, we must finally end the use of coal. In Europe, there is talk that this will be done by 2030, in the rest of the world by 2050. But many obstacles remain and the disparities between countries are immense. For the IPCC, the solutions are legion and renewable energy remains the best bet. The report estimates that by 2050, it will represent 70% to 85% of the world’s energy production. Yet, in order to achieve carbon neutrality by mid-century, energy production methods cannot be seen as the only solution. Industry as a whole must play a major role, to the point that CO2 emissions are lowered by approximately 75% to 90% in 2050, when compared to those of 2010. Cities must also be involved. Transforming urban systems and infrastructures in order to limit global warming must involve changes regarding land usage and urban planning, as well as emissions reductions through changes to transportation systems and building construction. Finally, in order to keep to the 1.5°C limit, agriculture must drastically review and revise it production model and start working towards the restoration of biodiversity. Changes to the way land is used at the global and regional levels are therefore more than necessary. Pastures, land that is not used for grazing or crops, as well as forested and re-forested areas will be, on a large scale, the best method of decarbonization over the next thirty years.

5. With the bonus of societal benefits
One essential question, which must be answered, remains: are such economic upheavals compatible with the fight against poverty and more generally with the development goals set by the United Nations? Once again, the report responds in the affirmative. By putting into place actions that will limit global warming, the risk of the impacts associated with rising temperatures and the costs linked to them will also be limited, the report states. Any limitation placed on global warming will also reduce the risks of inequality and poverty, the scientists remind us. Guaranteeing equity and ethics will also be an asset in facing the inevitable effects of an increase in global temperatures, even one of 1.5°C, they continue. "Context-specific adaptation measures will have benefits in reducing poverty." Well orchestrated, "they can help secure access to water and food or improve the health" of populations. All this implies, however, that greenhouse gas adaptation and mitigation systems be supported by significant investments and technological innovations, the IPCC insists.

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