Human influence on the climate system is clear and growing, with impacts observed on all continents. However, options are available to adapt to climate change and implementing stringent mitigations activities can ensure that the impacts of climate change remain within a manageable range.

These are among the key findings of the Synthesis Report released by the Intergovernmental Panel on Climate Change (IPCC) on Sunday 2 November. The Synthesis Report distils and integrates the findings of the IPCC Fifth Assessment Report produced by over 800 scientists and released over the past 13 months – the most comprehensive assessment of climate change ever undertaken.

“We have the means to limit climate change,” said R. K. Pachauri, Chair of the IPCC. “The solutions are many and allow for continued economic and human development. All we need is the will to change, which we trust will be motivated by knowledge and an understanding of the science of climate change.”

The Synthesis Report confirms that climate change is being registered around the world and warming of the climate system is unequivocal. Since the 1950s many of the observed changes are unprecedented over decades to millennia. “Our assessment finds that the atmosphere and oceans have warmed, the amount of snow and ice has diminished, sea level has risen and the concentration of carbon dioxide has increased to a level unprecedented in at least the last 800,000 years,” said Thomas Stocker, Co-Chair of IPCC Working Group I.

The report expresses with greater certainty than in previous assessments the fact that emissions of greenhouse gases and other anthropogenic drivers have been the dominant cause of observed warming since the mid-20th century.

The impacts of climate change have already been felt in recent decades on all continents and across the oceans, says the report. The more human activity disrupts the climate, the greater the risks. Continued emissions of greenhouse gases will cause further warming and long-lasting changes in all components of the climate system, increasing the likelihood of widespread and profound impacts affecting all levels of society and the natural world, the report finds.

There are multiple mitigation pathways to achieve the substantial emissions reductions over the next few decades necessary to limit, with a greater than 66% chance, the warming to 2oC – the goal set by governments, said the IPCC. “It is technically feasible to transition to a low-carbon economy,” said Youba Sokona, Co-Chair of IPCC Working Group III. “But what is lacking are appropriate policies and institutions.”

The Synthesis Report finds that mitigation cost estimates vary, but that global economic growth would not be strongly affected. In business-as-usual scenarios, consumption – a proxy for economic growth – grows by 1.6 to 3 percent per year over the 21st century. Ambitious mitigation would reduce this by about 0.06 percentage points. “Compared to the imminent risk of irreversible climate change impacts, the risks of mitigation are manageable” said Sokona. These economic estimates of mitigation costs do not account for the benefits of reduced climate change, nor do they account for the numerous co-benefits associated with human health, livelihoods, and development.

Emission trading

In a reaction, the IETA (the International Emissions Trading Association) noted that the IPCC recognizes “the benefits of pricing carbon in fighting climate change” in its fifth assessment report. Released one month before negotiators meet in Lima, Peru to hammer out the draft negotiating text for a 2015 deal, to be concluded in Paris, the IPCC Fifth Assessment Report states: “Mechanisms that set a carbon price, including cap and trade systems and carbon taxes, can achieve mitigation in a cost-effective way.” It adds that effectiveness has been varied, due to design and national circumstances.

The report also notes that since 2007 – when the Fourth Assessment Report was released – there has been an increase in mitigation efforts, with 67% of the world’s greenhouse gas emissions subject to national legislation or reduction strategies by 2012, compared with 45% in 2007. However, there is yet to be a “substantial deviation” in global emissions trends, the IPCC adds, and with many of these plans still in infancy, their long term effectiveness is difficult to gauge.

“Business has been saying it, more than 70 national governments got behind it, and now the scientists are saying it: carbon pricing is needed in the fight against climate change,” says Dirk Forrister, IETA’s CEO and President. “The past few years have seen a surge in market-based policies to price carbon and thus cut emissions, from Beijing to Seoul to Sacramento – and more programmes are on the way.”

“The Lima talks need to start laying the foundation for these efforts to be recognised and properly counted in a future climate regime – this will be essential to building public  confidence that targets can be achieved without compromising economic growth.”

The IPCC report also highlights the efficiencies that linkages between policies can bring, such as lower costs and less risk of carbon leakage, even when two different approaches are linked such as a cap-and-trade market and a performance standard.“With nations likely to employ a diverse array of pricing policies , it will be important to allow linkages to emerge between the different systems – both to improve the overall economic performance and to ease the administrative burdens on businesses operating across borders,” says Jeff Swartz, IETA’s director of international policy. “IETA has proposed provisions for markets for the 2015 deal and is engaged with negotiations for a Framework for Various Approaches and New Market Mechanism, which could provide this key link.”

Sources: European Climate Foundation, IPCC, IETA. For the full IPCC AR5 report, see www.ipcc.ch. IETA’s Policy Briefing on market provisions for the Paris agreement is available online. IETA’s most recent responses to the UNFCCC on market mechanisms, see here.