More than 200 climate science and policy researchers, economists and social scientists have descended this week on Keble College in Oxford for a two-day conference entitled “1.5 degrees: Meeting the challenges of the Paris Agreement.” The conference has been organised by the Environmental Change Institute at the University of Oxford.

Up for discussion is what kind of evidence the scientific community will need to produce to feed into a special report on 1.5C, requested by the United Nations after Paris and due for publication in 2018.

High profile start

A public event on Tuesday night in Oxford town hall featured several of the architects of the Paris Agreement, ensuring the conference got off to an optimistic start.

Janos Pasztor, senior advisor to the UN Secretary-General, spoke about the policy community passing the baton to the scientists. He told the audience:

“Clearly, a policy decision was taken first, but 1.5C and 2C are not inconsistent with science. I’m not worried.”

Laurence Tubiana, French ambassador for the climate negotiations, offered an insight into the diplomatic processes credited with the success of the Paris agreement. Carbon Brief spoke to Tubiana afterwards about the questions scientists now need to answer about 1.5C. She told us:

“The scientists have to be very clear on the reality: where we are with the carbon budget that is left; how much we have to peak by 2020…And it’s very important that the impacts are clearly understood – the difference between 1.5C and 2C and beyond.”

Climate impacts

A key theme for day one at the 1.5C conference was understanding the impacts on natural and human systems of 1.5C of warming, and how they might compare to those at 2C. In the video below, Carbon Brief talks to:

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.

Dr Valérie Masson-Delmotte, senior scientist at the Laboratoire des Sciences du Climat et de l’Environnement and co-chair of IPCC Working Group I.

Dr Friederike Otto, lecturer in physical geography at the University of Oxford and research fellow at Environmental Change Institute.

Prof David Keith, Gordon McKay professor of applied physics and professor of public policy at Harvard University.

Dr Joeri Rogelj, research scholar at the International Institute for Applied Systems Analysis (IIASA).

Carbon Brief asked a number of attendees of the conference about the impacts of 1.5C of warming, and how they might compare to 2C.

Before the science talks, Dr Anna Pirani, head of the IPCC’s Working Group 1 Technical Support Unit, reminded everyone of the short timeline they’re working to. To be assessed in the IPCC’s special report on 1.5C, papers must be submitted by October 2017 and accepted by April 2018.

Pirani also revealed the draft outline of the 1.5C report, drawn up at a scoping meeting in July. The proposed title and chapter headings will be submitted for approval in October and are, therefore, still subject to change.

Draft outline of 1.5C special report looks like this (shld be up on IPCC website today, we're told) #1point5 pic.twitter.com/GzxPbFjwlQ — Roz Pidcock (@RozPidcock) September 21, 2016

After a summary of the warming and impacts we’ve seen so far by Dr. Valérie Masson-Delmotte, senior scientist at the Laboratoire des Sciences du Climat et de l’Environnement and Co-chair of IPCC Working Group I, Prof Richard Betts, head of climate impacts research at the Met Office Hadley Centre and chair in climate impacts at the University of Exeter, discussed the importance of climate information at a regional level, not just globally.

Interesting point from @richardabetts: hard to assess CO2 fertilisation when 1.5C cd be anything from 430ppm to 550ppm #1point5 — Oliver Morton (@Eaterofsun) September 21, 2016

Prof Sonia Seneviratne, from the Institute for Atmospheric and Climate Science at ETH Zurich, raised an important question that the special report will need to address: are the impacts at 1.5C for extreme weather, biodiversity and crop yields, for example, sufficiently different than at 2C to make the more ambitious target worth pursuing?

Benefits of #1point5 v 2°C warming must be balanced v mitigation impacts – esp. on land use and food production -Prof Seneviratne #biofuels — Ben Abraham (@benabrahamnz) September 21, 2016

Prof Pete Smith, chair in plant & soil science at the Institute of Biological and Environmental Sciences, University of Aberdeen, summarised what a pathway to 1.5C might mean in terms of “negative emissions” and land use. This included the point, echoed by other speakers this morning, that the special report will need to consider not only the direct impacts of climate change, but also the impacts of steeper mitigation. There will be more on Wednesday.

Pete Smith: We need to invest in test projects for negative emissions technologies "to see which ones have legs" #1point5 — Robert McSweeney (@rtmcswee) September 21, 2016

Rounding up the first morning session, Prof Yadvinder Malhi, head of ecosystems research at the Environmental Change Institute at the University of Oxford, touched on the risk of an additional 0.5C of warming for biodiversity. The higher the temperature, the greater the risk of reaching a tipping point from which an ecosystem can’t recover, he said.

Jason Lowe: Special report will need to address impacts of overshoot and temporary resilience #1point5 — Roz Pidcock (@RozPidcock) September 21, 2016

After a well-earned coffee break, the plenary session turned its focus towards the human impacts of a 1.5C warmer world. Dr Maarten van Aalst, director of the Red Cross/Red Crescent Climate Centre, discussed the importance of considering people’s overall vulnerability – not just to climate change – and focusing on building resilience.

People facing #climatechange “have to confront choices that have to do with much more than climate alone” @mkvaalst #1point5 — Thomson Reuters Foundation News (@TRF_Stories) September 21, 2016

This point was picked up by Dr Stéphane Hallegatte, a senior economist in the climate change group at the World Bank, who highlighted that development “is more important than targeted adaptation” for reducing the potential impacts of climate change.

@hallegatte: To reduce climate impacts on people, "good development" is more important than targeted adaptation #1point5 — Robert McSweeney (@rtmcswee) September 21, 2016

He also cautioned that a 1.5C limit shouldn’t affect the design of adaptation strategies as they need to account for the possibility of higher temperatures anyway – in case we miss the 1.5C goal.

Parallel sessions

The afternoon’s sessions saw attendees choose between four topics: mitigation options, the sensitivity of natural systems, human impacts of 1.5C, and implications for adaptation.

The mitigation session saw a series of presentations about emotive, sometimes controversial topics. Prof Alice Larkin at the Tyndall Centre in Manchester focused on aviation and shipping emissions and came to the stark conclusion that both sectors face potential unfeasible reductions in their emissions intensity if they are to “do their share” of staying within the 1.5C limit.

For aviation to do its bit for good chance of staying within 1.5C, @AliceClimate says needs 20% intensity reduction PER YEAR #1point5 pic.twitter.com/z8XDwRCBSY — Leo Hickman (@LeoHickman) September 21, 2016

The session also included a number of presentations about negative emissions technologies and geoengineering. Henrik Karlsson of Biorecro countered the mood of the room by being very positive about BECCS (bioenergy and carbon capture and storage) arguing that it had already been proven at a commercial scale.

Let's just say that Henrik Larsson of Biorecro is *very* optimistic about negative emissions from BECCS #1point5 pic.twitter.com/Sg4v5OJowr — Leo Hickman (@LeoHickman) September 21, 2016

Dr David Keith, professor of public policy at the Harvard Kennedy School, concluded the session with a plea that the audience reassess their negative preconceptions about solar geoengineering.

I detest seemingly objective/scientific claims that hide the hard value choices, hard politics. Solar #geoengineering is a hard choice. https://t.co/xedAx72bmr — David Keith (@DKeithClimate) September 21, 2016

The natural systems session spanned a range of topics, from Antarctic sea ice to wheat production in Tunisia and reindeer in the Arctic tundra.

Dr Carl-Friedrich Schleussner from Climate Analytics began by explaining how the large majority of tropical coral reefs are at risk at 1.5C, whereas all will be at risk at 2C. Greater habitat disruption to grow bioenergy might mean that some impacts of 1.5C are worse for biodiversity than those at 2C, warned Dr Jeff Price, senior researcher at the University of East Anglia.

"0.5C will make a huge difference in the African region in terrestrial point of view" says @Dr Jeff Price #1point5 — Boi Tshwene (@BoiChaz) September 21, 2016

Prof Bruce Forbes from the Arctic Centre at the University of Lapland reminded the audience that regional warming in the Northwest RussIan Arctic already exceeds 1.5C, with consequences for reindeer feeding and survival.

Impacts at 2C not just a bit bigger than #1point5: potential for different sign of change in polar regions. Great talk by @emilyshuckburgh — 1p5deg (@1p5deg) September 21, 2016

In the adaptation session, chaired by co-chair of IPCC Working Group II Dr Debra Roberts, presenters looked at the implications for coping with a 1.5C warmer world.

Prof Robert Nicholls, professor of coastal engineering at the University of Southampton, started things off by looking at how sea level rise would affect the some of the world’s largest deltas. He described how limiting global temperature rise to 1.5C gives deltas more time to adapt to rising seas, but “does not avoid the [eventual] impacts due to the commitment to sea level rise which continues for centuries”.

Prof Robert Nicholls of @unisouthampton: 1.5C limits impact of sea level rise on deltas – especially beyond 2100 #1point5 — Robert McSweeney (@rtmcswee) September 21, 2016

Nicholls was followed by a series of presentations taking us through the different sectors and facets of adaptation. Prof John Antle discussed adapting agriculture and food systems for 1.5C, while Dr Mike Morecroft spoke on building ecological networks to protect biodiversity. Prof Nijavalli Ravindranath talked us through developing adaptation strategies through assessing vulnerability, and Meghan Bailey presented her PhD research on adaptation financing. Finishing the session was Patrick Pringle, the deputy director of UK Climate Impacts Programme (UKCIP), who discussed the tricky task of implementing adaptation actions.

Patrick Pringle: "We need to value the cement as much as the bricks." – bring together research, policy and practice #1point5 — Robert McSweeney (@rtmcswee) September 21, 2016

Day one rounded off with a final plenary discussion on the moral implications of the 1.5C goal.