An agreement produced by the 20th Conference of the Parties in Lima, Peru, noted ‘with grave concern’ that countries’ current pledges on emissions reductions are insufficient to keep global temperature rise within either 2°C or 1.5°C of pre-industrial levels. This is indeed a serious concern because temperature changes of just a few degrees are enough to change the climate significantly. Rising sea levels, melting mountain glaciers and polar ice caps and increases in extreme precipitation have already been observed. These trends will continue with ongoing greenhouse gas emissions, and it is expected that we will continue to see an increase in extreme high sea levels, an increase in the intensity of the heaviest rain, and changes in the global distribution of rainfall.
The Parties to the United Nations Framework Convention on Climate Change (UNFCCC) have until March 2015 to provide updated emissions pledges. The 1994 UNFCCC protocol aims to achieve the ‘stabilization of greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system’. The protocol made it clear that countries have ‘common but differentiated responsibilities and respective capabilities’, implying that developed nations who are responsible for historical emissions should make the deepest cuts. An agreement drafted during COP 20 added the phrase ‘in light of different national circumstances’. The new deal to some extent blurs the distinction that has existed between developed and developing nations. However, it remains to be seen exactly how the responsibility to reduce emissions will be spread between different countries.
China’s per capita emissions are now at EU levels, but when total cumulative emissions of greenhouse gases are taken into account – carbon dioxide is long lived in the atmosphere so the total emissions over time are what matter – the five countries most responsible for global warming on a per capita basis are the United Kingdom, the United States, Canada, Russia and Germany. When countries are ranked by their absolute contribution to global warming so far, the top five are the United States, China, Russia, Brazil and India, and the United Kingdom is number seven on the list. Of course, the reason for the United Kingdom’s high ranking on both these lists because it industrialised early. Different studies disagree on the exact ranking, but on a per capita basis the developed nations bear most of the responsibility for the temperature increases we have already seen. Nevertheless, there is increasingly a need for the richer developing nations to take some action as well.
The coming months are a critical time for the global climate change negotiations. There have already been encouraging signs: the United Kingdom and the EU have led the way with ambitious pledges, and China and the United States have taken a positive step forward with their recent bilateral agreement. However, more needs to be done. It is right that the United Kingdom and the EU are leading the way on this, but it is also vital that the political will remains to tackle climate change as we move into a crucial stage of the negotiations. Action is urgently needed – in order to avoid temperatures rising more than 2°C above pre-industrial levels, global emissions should peak by 2020. Delaying the peak in emissions until 2030 will increase the costs of taking action and make it very difficult to keep to this target. Meeting the 2°C target will require the leaders of the developed world to continue to increase the level of ambition over the coming months.