The primary objective of the climate agreement reached in Paris in December of 2015 is to limit global warming to “well below 2o C (3.6oF)” and to “pursue efforts” to limit warming to 1.5oC. In order to achieve that objective, countries submitted information outlining the efforts that they were willing and able to make beginning in 2020 to reduce global warming. In total, some 160 “Intended Nationally Determined Contributions (INDCs)” were submitted in preparation for the Paris conference. It became evident during the course of the Paris Conference, based on preliminary analyses performed by several organizations, that the INDCs were not sufficient to meet the stated objective of holding global warming to less than 2oC.
A new and comprehensive assessment of the Paris Agreement was published on 30 June 2016 in the journal Nature. The title of the publication is, “Paris Agreement climate proposals need a boast to keep warming well below 2oC”. The conclusion reached is that even if all of the INDC’s are fully met, and that “climate action continues after 2030 at the level of ambition that is similar to that of the INDCS”, there is 50% probability that global warming will exceed 2.7oC by 2100. Moreover, there is a 34% probability that global warming will exceed 3.0oC and a 10% probability that it will exceed 3.7oC.
Unfortunately, the results summarized above are based on the most optimistic of the four scenarios examined in the study! Arguably, as the study demonstrates, under less optimistic assumptions concerning mitigation efforts, global warming could exceed 4oC by 2100.
The study concludes that even if all of the INDCs are fully implemented, global greenhouse gas emissions in 2030 will reach approximately 53 billion tons of CO2e per year, which is well in excess of current emission levels. Moreover, the cumulative carbon budget necessary to keep global warming to less than 2oC will be “virtually exhausted” by 2030.
The only scenarios that are consistent with the 2oC objective require: (1) the complete phase out of CO2 emissions from energy production and industrial applications within the time span of approximately 30 years, and (2) the rapid deployment on an industrial scale of negative emission technologies that are capable of removing vast amounts of CO2 from the atmosphere and sequestering it geologically. By 2050 it would be necessary to capture and sequester approximately 10 billion tons of CO2 per year.
The study concludes that, “substantial enhancements or over-delivery on current INDCs by additional national, sub-national and non-state actions is required to maintain a reasonable chance of meeting the target of keeping warming well below 2oC”.
It is hard to underestimate the significance of this study. It provides a comprehensive and accurate assessment of the current climate crisis. The only rational conclusion that one can draw is that the principal objective of the Paris Agreement of holding the increase in global warming to “well below 2oC” simply cannot be achieved. It is naïve in the extreme to believe that there is some magical set of “enhancements” to the INDC’s that will be adopted during the coming decade that will somehow result in a “reasonable chance” of meeting the 2oC objective.
The continued pursuit of a goal that is clearly unattainable is a fool’s errand! The development of increasingly fanciful emissions scenarios based on progressively less realistic technological assumptions is highly counterproductive. It conveys the impression that the scientific community is simply out of touch with reality, and as consequence leads many to believe, wrongly, that the underlying climate science itself is similarly suspect.
It is time for the scientific and engineering community to state openly and unequivocally that human civilization is entering a new and admittedly dangerous climate era – and that there is no realistic way to limit global warming to 2oC. Effort needs to be re-directed toward finding ways to minimize the impact of the pending climate crisis and to focus on finding realistic ways to rapidly phase out the use of fossil fuels, even if the 2oC objective is no longer obtainable.