Prior to COP21 in Paris, December 2015, policy makers agreed that a suitable target for the UN summit was to keep global temperature rises caused by greenhouse gas emissions below 2 ˚C, a figure commensurate with a pre-industrial era (for a critique of this figure and the use of surface temperature as a catch-all indicator of climate change see Victor and Kennel 2014). During the COP, largely due to the lobbying of Pacific Island nations, this target was revised to 1.5 ˚C and entered into the wording of the Paris Agreement.
In an often cited paper produced by Christophe McGlade and Paul Ekins (2015), they calculate that if the planet is to have a 50% chance of keeping temperatures below 2 ˚C this century, cumulative greenhouse gas emissions need to be limited to about 1,1000 gigatonnes of carbon dioxide. In their estimates, this means that around 80% of known reserves of coal, oil and gas would have to remain untouched. According to their findings:
globally, a third of oil reserves, half of gas reserves and over 80% of current coal reserves should remain unused from 2010 to 2050 in order to meet the target of 2˚C. (McGlade and Ekins 2015, p. 187)
McGlad and Ekins have modelled their findings according to current regional reserves, sensitive to Carbon Capture and Storage (CCS) technologies becoming available in the near future, which they note due to their expense and relatively late introduction will only have a modest effect before 2050. Obviously, these findings have certain geopolitical implications. The Middle East holds half of the ‘unburnable’ oil and gas reserves globally, whilst the Former Soviet States account for another third. The report recommends that 82% of global coal reserves remain unburned before 2050, indicating China and India as the countries that rely most on this resource. The scientists also determined that no oil or gas could be produced within the Arctic Circle if we are to meet the 2 ˚C scenario before 2050 (McGlade and Ekins 2015, pp. 189–190).

The 2 ˚C and now more ambitious 1.5 ˚C target, alongside the imperative to keep fossil fuels ‘in the ground’, has been the driver of much activism surrounding COP21, coupled with the improbability, if not the impossibility, of the UN negotiations to set enforceable limits of CO2 emissions (eg Climate Games).
‘The Paris Agreement’ that emerged on 12 December 2015 and described by journalist Marlowe Hood (2015) as a collective ‘Letter of Intent,’ is significant in that the international community did recognise that ‘climate change represents an urgent and potentially irreversible threat to human societies and the planet and thus requires the widest possible cooperation by all countries’ and the need to reduce greenhouse gas emissions (UNFCCC 2015, p. 1). The Agreement also emphasises the need to limit global average temperatures to ‘well below 2 °C above preindustrial levels’ and to pursue efforts to limit this increase to 1.5 °C (UNFCCC 2015, p. 2).
However according to Professor Kevin Anderson (2015), the Deputy Director of the Tyndall Centre for Climate, despite its good intentions the agreement ‘risks being total fantasy’ (Anderson 2015, p.437). His reasoning is that rather than requiring nations to reduce emissions in the short term, (as per McGlad and Ekins’ model), it assumes that sometime in the latter half of this century we would have developed sufficient ‘negative-emissions technologies’ to capture and contain excess carbon pollution from the atmosphere. Anderson points out that these technologies, initially being discussed by scientists as a worst-case scenario ‘Plan B’ if we were not able to manage a rapid shift into renewable energy sources, have become ‘The Plan.’ What is worse is that the speculative technologies on which they rely are not mentioned in the Paris Agreement, but nevertheless underwrite the claims being made, suggesting leaders are not willing to discuss them openly. Furthermore, Anderson is sceptical the international community will be able to achieve a 2 ˚C limit in the coming century, floating a figure of 4 ˚C or more on his blog (Anderson 2016).
Anderson flags Biomass Energy Carbon Capture and Storage (BECCS) as what government advisors believe to be the most promising of these technologies. He describes the process as follows:
Apportioning huge swathes of the planet’s landmass to the growing of bioenergy crops (from big trees to tall grasses) — which absorb carbon dioxide through photosynthesis as they grow. Periodically, these crops are harvested, processed for worldwide travel and shipped around the globe before finally being combusted in thermal power stations. The CO2 is then stripped from the waste gases, compressed (almost to a liquid), pumped through large pipes over potentially very long distances and finally stored deep underground in various geological formations (from exhausted oil and gas reservoirs through to saline aquifers) for a millennium or so. (Anderson 2015, p.437)
He predicts that proceeding with such an undertaking in the latter half of this century would require ‘decades of planting and harvesting of energy crops over an area of one to three times that of India.’ Simultaneously, the aviation industry is envisioning powering its aircraft with biofuel, and the shipping industry will no doubt soon follow. There may also be potential for biomass to develop into a potential feedstock, but he warns it is a very ‘risky insurance policy’ that deserves wider scrutiny.
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Marc Hudson interviews Kevin Anderson, 8 January 2016
Hood, Marlowe, 2015. ‘COP21: Less than meets the eye,’ AFP Correspondent, 21 December.