COMMENTARY

Is 1.5ºC achievable?

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AT the preparatory meetings for COP21 in Lima, Peru, delegates from countries that are most vulnerable to the impacts of climate change proposed changing the global temperature target from 2ºC to 1.5ºC.

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Over the advice of climate scientists, the change was adopted as an aspirational goal.

Hereafter, the targets will be qualified as “well below 2ºC above pre-industrial levels with efforts to limit temperature increase to 1.5ºC,” to use the language of the Paris Agreement.

The Industrial Revolution began in England in about 1750. However, the Intergovernmental Panel on Climate Change (IPCC) had been using 1875 as the base year for calculating global temperature.

Dr. Michael E. Mann, the director of the Penn State Earth System Science Center has determined that from 1875 our net carbon budget is about 3000 gigatons of which we have used about 2000 gigatons or approximately two-thirds.

Using another metric, the limit for 2ºC is 450 parts per million of carbon. The pre-industrial levels are 350 ppm. The current levels are 440 ppm, increasing by about 2.1 ppm every year. We will reach 450 ppm in about 20 years.

In an article that appeared in Scientific American last year, Dr. Mann, using 1750 as the base year, estimated that we will cross the climate danger threshold in 2036.

This gives us very little time to make the transition from fossil fuel to carbon free energy.

What must be done?
(1) All countries should fulfill, as best they can, the pledges that they made in Paris to reduce their carbon emissions. Inadequate as they are, it will at least help stabilize carbon concentrations in the atmosphere.

(2) Every country should consider a carbon tax. A harmonized price of carbon should be taken up and approved, if possible, in the 2020 meeting. If a uniform price cannot be adopted, for whatever reason, each country should promulgate and enforce a national carbon price. The revenue raised should be used for adaptation and mitigation measures.

(3) The public and private sectors should collaborate on technologies that will “decarbonize” our economies.

(4) And finally, everyone should be upfront and transparent in their efforts to attain the 1.5ºC goal.

Carbon capture and sequestration (CCS) should be the object of a Manhattan Project-type approach.

Two CCS technologies are worth serious consideration because they are relatively simple.

The first involves planting trees, tall grasses, cellullosic shrubs, etc. to absorb CO2 through photosynthesis. They will then be harvested and processed as fuel for thermal power plants that are equipped to capture the CO2 that they will emit, which will then be liquefied for long-term storage underground or used as raw material for new products.

The second is a machine that will capture atmospheric CO2 directly for sequestration in rock formations, saline aquifers, and empty oil and gas wells.

Such machines are already being used, albeit on a small scale, in Switzerland.

The aspects of this technology that need to be examined are whether it could be geoengineered and whether the storage sites could be made leak-proof for millenia.

Are these disruptive technologies?

We do not know. In quantities that will be significant, bioenergy crops would need enormous land areas that will compete with food production. Unless farm wastes can be used and whether there is net reduction of greenhouse gases that agriculture produces will make it worth it. Huge suction machines could have unknown effects on planetary weather and climate.

It is necessary to educate and train more climate scientists and skilled workers in the various disciplines of climate mitigation and control to study and operate all this.

When future meetings are convened for stocktaking and for ramping up country pledges, the matter of finance must be revisited and tackled head-on. Carbon pricing should be on the agenda.

Differentiation should be defined more precisely to make cost sharing acceptable.

We have only up to the middle of the century to attain the 2ºC temperature target and attempt to roll it back to as close to 1.5ºC as we are able.

Else, the next generation will inherit a 3ºC world.

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