The Fifth IPCC Assessment Report has at last been completed and made public. Since April 15th the (third) volume Mitigation of Climate Change has been made available, concluding the triad of the most awaited publication from the world of climate change science and policy at the international level. The only piece missing to complete the work of the Fifth IPCC Assessment Report on Climate Change is the Synthesis Report, the document summarizing the three volumes published in recent months, which will be approved and published in late October 2014 in Copenhagen.
The first volume confirmed human responsibility for climate change, the second outlined the impacts and risks that have and will come of it. IPCC’s third working group, of which I am one of the Vice Presidents, is trying to find solutions to the problem of future climate change through appropriate mitigation policies, namely the reduction of greenhouse gases.
Prepared by 235 authors from 57 countries, the third volume of the report integrates more than 38,000 comments received by more than 800 expert reviewers in the various stages of writing and revision, to answer this question: what can and should we do to limit climate change as much as possible in the coming decades?
The Point We Are At
One of the main messages emerging from the work is that, despite the new awareness and mitigation efforts put in place over the past decades, the emissions of greenhouse gases have increased more rapidly between 2000 and 2010 than in any other decade: the rate of emission growth of the past decade has been 2.2% per year, while in the period between 1970 and 2000 it averaged 1.3% per year. 78% of emissions derive from the use of fossil fuels and industrial processes. The forestry sector is the only one experiencing a decline in emissions, due to the reduction of deforestation and hence an increased capacity by forests to absorb carbon dioxide.
What We Can Expect
In the absence of more mitigation efforts than at present, the emissions increase (driven by population and economic growth in developing countries and insufficiently offset by significant improvements in energy efficiency in developed countries) will lead to an increase in average global temperature in 2100 of between 3.7 and 4.8 degrees centigrade in comparison with pre-industrial levels.
It is clear that if we continue on this path we will get adrift inexorably from the so-called “2-degree” target formalized in the COP 16 negotiations in Cancun (2010): the two-degree rise in temperature over preindustrial levels is recognized internationally as the threshold not to be exceeded if we are to comply with Article 2 of the UN Framework Convention on Climate Change (UNFCCC), which stabilizes global emissions to “prevent dangerous anthropogenic interference with the climate system.” But the Fifth IPCC Report also points out that this objective has become very difficult if not almost impossible to achieve by now, in the light of the levels of concentration of greenhouse gases already present in the atmosphere and expected in the coming years.
What Must Be Done And When
To close the 2-degree target gap, emissions must peak off as soon as possible and then decline by 40-70% within mid-century, reaching a total of zero in 2100. We need to act now, because any delay takes us adrift of any chance of a green transition that allows the decoupling of economic growth from the growth of greenhouse gas emissions, and significantly increases the mitigation costs. Mitigation options include actions for energy efficiency and decarbonization (renewable energy sources, nuclear power, carbon capture and storage of CO2 (CCS), bio-energy, reduction of deforestation and forest management, reduction and management of waste, carbon market, carbon taxation, reduction or removal of subsidies for fossil fuels, and overall changes in lifestyle). The IPCC report gives no recommendation for the most appropriate measures to be taken but limits itself to analyzing them all accurately, in order to provide policymakers with the tools to make informed, effective decisions.
The Ideal World
The optimal situation for dealing successfully and efficiently with the climate challenge is one in which all the countries of the world implement immediate mitigation actions, in which there is a single carbon price in a worldwide emissions market, and in which a combination of all the technological solutions and policies listed above is available and usable in all sectors (production and use of energy, industry, transport, agriculture, forestry, urban development). In this ideal world the costs of mitigation might be limited. But unfortunately this ideal world doesn’t exist….
Costs, Benefits And Investments
In an ideal world scenario of mitigation as described above, one that meets the two-degree target, the costs are estimated at between 1 and 4% of worldwide GDP in 2030 and between 2 and 6% in 2050. These are only the direct costs, which do not take into account the benefits that would result from maintaining a climate more similar to today’s, from having reduced air pollution, lower impacts on ecosystems, water and land use, as well as greater energy security. But the costs will increase rapidly if the mitigation measures are applied late, or if some of the currently available technologies (nuclear or CCS for example) were not fully applicable, or if the resources for necessary investments were not forthcoming….
For the first time, the IPCC Report also assesses the investments needed to achieve the two-degree target: in the next two decades (2010-2029) investments in clean energy production technologies will have to increase by 100%, that is redouble, while investments in fossil fuels decrease by 20%.
Also An Ethical Question
From the data presented in the report, which will be used as a scientific basis in international negotiations under the UNFCCC in the coming years, there are striking inequalities in per capita emissions of greenhouse gases: high-income countries have per capita emissions even nine times higher than those of the poorer countries. The issue of climate change is not, therefore, just an environmental issue but also a matter of economic and social equity that forces us to face the impacts that the climate challenge poses, which are more severe in the developing (and hence more vulnerable) countries. Most of the growth in emissions that has taken place since 1970 is the responsibility of the industrialized countries, associated with their economic development. The recent rise in emissions, and that foreseen for the future, is instead linked largely to the regions in the developing world, which are growing at a very rapid pace. Hence it is necessary to establish a cooperation between countries that implies an ethical, responsible commitment on the part of those that have so far contributed most to the problem, i.e. the developed countries, and a likewise ethical, responsible commitment on the part of those that in the future are destined to exceed the tolerable limit of human interference with the climate system.