The Paris Agreement reached during the United Nations conference on climate change (COP21) in December last year included two temperature goals: one, holding the global average temperature increase to well below 2°C; and two, actively pursuing efforts to limit the temperature increase to 1.5°C. Last Friday, the historic Paris Climate Accord was signed by 175 countries at a ceremony in New York hosted by the United Nations Secretary General Ban Ki-moon. According to an article published in the Earth System Dynamics journal this year on 21 April, the impacts of a 2°C average temperature increase are far more significant than we think, with even a 1.5°C average increase adversely effecting economies and environments around the world. This exemplifies why Governments have to do far more than sign onto the Accord.

The article entitled ‘Differential climate impacts for policy-relevant limits to global warming: the case of 1.5°C and 2°C’ reports the findings of collaborative research by esteemed physicist and climate scientist Carl-Friedrich Schleussner from the Potsdam Institute for Climate Impact Research and his colleagues from Germany, Switzerland, Austria and the Netherlands. Their research assesses the impacts of climate change at both temperatures and includes extreme weather events, water availability, agricultural yields, sea level rise and the risk of losing coral reefs. According to these authors, although the two temperatures limits were frequently mentioned in the lead up to Paris in December last year, a greater understanding of the differences in climate impacts at 1.5 degrees vs. 2 degrees Celsius is sorely needed.

...if global temperatures continue to increase the impacts on ecological systems will accelerate

Recent decades have seen an increase in climate impacts, and scientists are now able to attribute many of these impacts to anthropogenic Carbon Dioxide (CO₂). This essentially means that CO₂ emitted from human activity has been proven to impact the environment, and if temperatures continue to increase the impacts on ecological systems will accelerate. For this reason, any decisions made by Governments in regard to climate change and effect need to be informed by the best available science that is capable of understanding the impacts, designing and implementing realistic and appropriate mitigation strategies such as solar photovoltaic (PV) infrastructure, carbon sequestration and carbon pricing mechanisms. It is also important that impacts are understood and mitigation strategies implemented on a regional as well as on a worldwide basis, as typical weather and climate patterns and environments are highly variable across the world.

The ‘Differential climate impacts for policy-relevant limits to global warming: the case of 1.5°C and 2°C’ article reports that there are substantial differences between the 1.5°C and 2°C climate change scenarios. In terms of extreme heat events, the additional 0.5°C above 1.5°C of warming marks a significant shift from the upper limit of current natural variability to a new climate regime. This shift is particularly significant in tropical regions. According to the authors of the report, an additional 0.5°C is also likely to be extremely problematic for the future of tropical coral reefs, with evidence pointing to almost all tropical coral reefs worldwide being at risk of severe degradation due to bleaching from 2050.

With respect to rainfall, the authors report marked regional differences. Reductions in water availability in the Mediterranean region is likely to nearly double from 9% to 17% between a 1.5°C and 2°C scenario. Under a 1.5°C scenario the duration of dry spells in the Mediterranean are likely to increase by 7%, while under a 2°C scenario the increase in duration could be as much as 11%. Tropical regions such as Central and northern South America could face substantial reductions in crop yields. These reductions could be particularly significant for wheat and maize production. According to the authors, the best estimate sea level rise under a 1.5°C would be approximately 30% lower than the anticipated 50cm rise under a 2°C scenario. A 50cm rise is likely to inundate low lying areas around the world, increasing the risk of flooding and forcing the relocation of millions of people.

Read the ‘Differential climate impacts for policy-relevant limits to global warming: the case of 1.5°C and 2°C’ article here

The ‘Differential climate impacts for policy-relevant limits to global warming: the case of 1.5°C and 2°C’ article is one that global Government advisors and the general public need to read and understand. Signing the Paris Accord is obviously important as a symbol of unity of purpose in fighting global climate change, however if Governments fail to implement the requisite strategies after signing it, the value of their signature is questionable at best. The general public needs to understand this article and its implications in order to maintain pressure on their Governments to design and implement realistic and appropriate mitigation strategies that are based on the best available scientific information.

The rapid increase in the implementation of solar photovoltaic (PV) infrastructure and carbon pricing mechanisms around the world exemplify the range of options that Governments already have at their disposal to fight climate change. Initiatives to fight climate change are urgently needed worldwide now as well as in the future, as the impacts of a 2°C average temperature increase are far more significant than we think.