An agreement is thought to have been agreed following talks in Paris to produce a deal on carbon emissions with the aim of limiting global warming and climate change.
Prof. John Shepherd CBE FRS, National Oceanography Centre, University of Southampton, said:
“The Paris Agreement includes some welcome aspirations – especially that ‘to achieve a balance between anthropogenic emissions by sources and removals by sinks of greenhouse gases in the second half of this century’.
“However, few people realize just how difficult it will be to achieve that goal, even with a 50 year window in the timing. Since the only mechanism remains voluntary national caps on emissions, without even any guidance on how stringent those caps would need to be, it is hard to be optimistic that these goals are likely to be achieved.”
Prof. Sir Brian Hoskins, Chair of the Grantham Institute, Imperial College London, said:
“The Paris agreement is the culmination of more than 20 years of negotiation. With it the countries of the world have recognised that they all have to work together to tackle the shared problem of dangerous climate change caused by human activities. We are now looking towards the post- fossil fuel era that will give new opportunities for technological, economic and social development that is truly sustainable.”
Prof. Chris Rapley CBE, University College London, said:
“Time will reveal the true nature of the COP21 deal. From epic turning point, to naive expression of hope, it is the real-world actions that follow which will decide. The transformation of the energy system, the economic system and politics that must now follow will be fought by the risk-blind and powerful forces of the status quo. But those of us who wish to build a better world, illuminated by wisdom and evidence, have today delivered a statement of intent that they will need to reflect upon with care. The tide has turned, and they can either swim with it, or against it. But the current has surged.”
Dr Emily Shuckburgh, Deputy-Head, Polar Oceans, British Antarctic Survey, said;
The ice core and observational records show so strikingly how as humans we have dramatically altered our global atmosphere in such a short time, with all the attendant risks to this and future generations. Today though we have seen another side of humanity. We have seen an unprecedented demonstration of how global cooperation has the potential to steer us onto a pathway to a safer future. The science tells us this will be a monumental challenge, but equally it is one abounding in opportunities for those who chose to seize them.
Prof. Corinne Le Quéré, Professor of Climate Change Science and Policy at the University of East Anglia and Director of the Tyndall Centre for Climate Change Research, said:
“The final draft text recognises the imperatives of the science community to tackle climate change. The three key elements to do it are there in some form: keep warming well below two degrees, practically move away from fossil fuels, and review each country’s contribution every five years so they scale up to the challenge. The emissions cuts promised by countries now are still wholly insufficient, but the agreement as a whole sends a strong message to businesses, investors, and citizens that new energy is clean and fossil fuels belong to the past. There is a lot of work ahead of us to make this happen.”
Prof. Michael Grubb, Professor of International Energy and Climate Change at UCL, said:
“With this agreement, the rich world has got the universal participation it has sought for 15 years. It may also herald a revolution in international governance. The west must now keep its side of the bargain by delivering steeper emission reductions and the finance agreed.”
Dr Stephan Harrison, College of Life and Environmental Sciences, University of Exeter, said:
“The agreement in Paris which aims to keep global warming to below 2C and even below 1.5C is extremely welcome. However, we should also be cautious. It is clear that the 1C temperature rise over pre-industrial levels that we have seen so far has triggered a whole range of effects including widespread melting of mountain glaciers, significant sea level rise, devastating droughts, and flooding in various parts of the world. These effects are likely to get much worse with even modest future temperature increases. Keeping temperatures to manageable levels also assumes that we know what the precise link is between atmospheric greenhouse gas concentrations and the global temperature response. We don’t know this, nor the nature and strength of natural feedbacks in the climate system that might drive future warming”.
Dr Ilan Kelman, UCL, said:
“For all that is encouraging in the draft agreement, the time scales and lack thereof, as expected, are worrying. Little substantive will happen until 2020 whilst clear deadlines for specific targets are generally absent. Even if this agreement is accepted in Paris, plenty of opportunities remain for governments to change and for legislatures to fail to ratify. It will be particularly difficult to deal with the US Congress.
“The starting point of USD 100 billion per year is helpful, but remains under 8% of worldwide declared military spending each year.”
Prof. Bill Collins, Professor of Atmospheric Chemistry and Earth System Modelling, University of Reading, said:
“This is the most ambitious agreement on climate change we have ever seen and if the ambitions could be achieved then this would bring huge benefits to all nations in limiting the damaging effects of temperature and sea level rise. It is very concerning though that the statements on the emissions reductions have been removed. How are we going to reach our objective unless we set out in the right direction? The cuts needed are going to be around 70% by 2050. Until the governments accept this we should restrain our optimism.”
Mr Asher Minns, Tyndall Centre for Climate Change Research, University of East Anglia, said:
“Climate science communication has a new challenge to rise to because if the likely way to keep temperature well below 2C is by overshooting and reversing global temperature, it means new conversations to engage people with the impacts of global climate change policy that is designed for extreme weather to be worse before it gets better.”
Prof. David Reay, Professor of Carbon Management, University of Edinburgh, said:
“This is a huge breakthrough. Those long nights of negotiations have paid dividends. Legally-binding, a robust ratchet mechanism, and strong reporting requirements – impressive. If adopted, the Paris agreement will become the first concrete step on our collective way towards avoiding dangerous climate change. There will be bumps in the road ahead, steep inclines and muddy wallows to overcome, but Paris has skilfully avoided hitting a climate change dead end.”
Prof. Piers Forster, Professor of Climate Change, University of Leeds, said:
“It’s a Christmas miracle! We really have the best deal possible. The ambitious long-term target will prevent sea-level rise and help food security and corals in particular. So unexpected was this agreement that we know very little about plausible socioeconomic pathways that might get us there. But in some ways the answer is simple, we need everything a we need it now – a true world revolution. We need renewable energy, nuclear power, fracking, zero-carbon transport, energy efficiency, housing changes. Even international aviation and shipping that were excluded from this report will need to be tackled within the next few years. Especially, We will also need huge amounts of negative emissions from carbon capture and storage/afforestation.
“Controls of short-lived climate pollutants also become more important, especially methane from agriculture and soot from diesel transport and wood stoves.”
Prof. Lord Julian Hunt, Emeritus Professor of Climate Modelling, UCL, said:
“The Paris agreement is welcome for being logical and transparent. One aspect is the role of citizens and government in urban areas. These will be where more than 70 percent of global population will live by end of century and will be responsible for most energy use. But depending on whether urban planning and lifestyle is like in cities such as Dallas, or Riyadh, or like Hong Kong or Paris, the global temperature target of 1.5 deg will fail to be met or will succeed. Governments need to address this challenge urgently.”
Prof. Mark Maslin, Professor of Climatology, UCL, said
“The COP21 agreement is an amazing achievement. The first time since Kyoto in 1998 have all 196 countries of the UN negotiated a legal climate change agreement. The agreement attempts to balance ‘climate justice’ and ‘differentiated responsibilities’ and could limit warning to ‘well below’ 2 deg C. Most importantly there will be 5 yearly reviews which allow the agreement to be tightened if the world is looks like it will warm more than 2 see C. We must give full credit to the French negotiators who ensured that all countries were heard and their views were taken seriously. As a result we have a landmark international agreement which is flexible enough to ensure that climate change is contained and its damage on the poorest countries is compensated for.”
Prof. Nigel Arnell, Professor of Climate System Science, University of Reading, said:
“Today’s agreement marks a big step in our attempts to curb climate change. The goal of limiting the rise in global temperature to well below 2oC – and to work towards 1.5oC – is more ambitious than many would have thought just a couple of years ago. But, as the agreement points out, the pledges that have currently been made are not in themselves sufficient to achieve this target. The agreement includes a commitment to update pledges and make them more progressive, but the text is rather vague on the level of overall ambition: it does not specify a date for the peaking of emissions, and specifies only that reductions should lead towards ‘greenhouse gas emissions neutrality’ in the ‘second half of the century’.
“There is a clear need now for the research community to work out what reductions in emissions will be needed to meet the new ambitious temperature target, to identify the new technologies and institutions that will be necessary to achieve these reductions, and quantify what impacts will remain and the adaptations that will be necessary.”
Prof. Tim Palmer, Royal Society Research Professor in Climate Physics & Director of Oxford Martin Programme on Modelling and Predicting Climate, University of Oxford, said:
“Paris has shown all countries of the world taking the climate threat seriously, and this is to be applauded. The Paris agreement will help reduce the chances of dangerous climate change – though by exactly how much is hard to quantify. In particular, when we speak about targets of 2 degrees, or even 1.5 degrees, we should remember that climate science has yet to uncover a simple deterministic relationship between carbon emissions and the level of future global warming. Instead, the relationship is imprecise – even more so at the regional level – reflecting current uncertainties in many complex processes at play in the climate system. If we wish to reduce uncertainty in our estimates of future climate, governments must continue to invest in the basic science of the physical climate system.”
Prof. Myles Allen, Professor of Geosystem Science, University of Oxford, said:
“Is 1.5 degrees possible? Human-induced warming is already approaching 1 degree, and predicted to be at 1.2 degrees by 2030, so obviously 1.5 degrees will be a challenge. But the IPCC’s “likely 2 degrees” carbon budget, regarded as ambitious but (just) doable, already limits warming due to CO2 alone to 1.5 degrees. So once we are on a path to net zero CO2 emissions, it will all come down to what we can do about other sources of warming. If we can stick to the IPCC’s 2-degree budget, and if UNEP is right that we can reduce peak temperatures by 0.5 degrees with action on methane and soot, and if Mother Nature is reasonably kind on the climate response, then 1.5 degrees is definitely still in the frame. But that is a lot of “ifs”.”
Further comment from Prof Myles Allen:
“Achieving a balance between sources and sinks of greenhouse gases in the second half of this century will require net carbon dioxide emissions to be reduced, in effect, to zero. It seems governments understand this, even if they couldn’t quite bring themselves to say so. To have a good chance of staying below 2 degrees, we need to aim for 1.5 degrees anyway, and it is sensible to acknowledge that 2 degrees itself is hardly “safe”. So, all told, a great outcome. Chapeau to French diplomacy.”
Prof. Neil Adger, Professor of Human Geography, College of Life and Environmental Science, University of Exeter, said:
“The agreement in Paris is fantastic. But the climate will provide a dose of reality. The agreement means, in effect, that countries of the world are not unduly worried about the costs of climate change, that they are bearable and long enough into the future. But in the long term, well before 2C of mean warming, the costs will be borne by vulnerable populations: farmers trying to eek out a living, elderly people not coping with extreme heat, and people in towns, cities and rural areas everywhere exposed to floods.
More and more people will bear a heavy cost from any delay in implementing what is agreed today in Paris.”