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expert reaction to IPCC AR5 WG2

Working Group 2 of the Intergovernmental Panel on Climate Change (IPCC) released their most recent report of the effects of climate change on our planet, including an assessment of how mitigation and adaptation could help the world respond to future climate effects. 


Dr Richard Harding, Senior Hydrologist from the Centre for Ecology and Hydrology (CEH), said:

“This first report of the IPCC fifth assessment concluded that human activities were already having an impact on our climate. This second report, assesses the considerable number of studies investigating the current and future impacts of these climate changes and possible adaption strategies.  The report concludes that warming increases the likelihood of severe, pervasive and irreversible impacts.  Some ecosystems and cultures are already at risk from climate change and there is a warning of irreversible changes.  In the future we will see increasing water scarcity and negative impacts on food production.  Climate change is increasing the risks of extreme events (flooding, high temperatures etc) and the impacts are greatest for the most disadvantaged communities.

“These impacts can be moderated by reducing their rate of change by mitigation, i.e. reducing our greenhouse gas emissions, and planning.  The impacts from recent climate extremes show a considerable vulnerability and exposure to present day variability. This vulnerability will increase as the climate changes.  The impacts, however, can be moderated adaptive planning, by all sections of society. A first step towards this adaption is reducing our exposure to current extremes – this is a double win, giving protection now and increased resilience in the future.

“This report is yet another wakeup call to take action on climate change.  It illustrates that it is not too late to take action but the consequences of inaction will be wide-ranging serious.”


Dr Daniela Schmidt, The Cabot Institute, University of Bristol, Lead Author of Chapter 6, said:

“We have a number of past records of natural climate change impacts on both terrestrial and marine ecosystems. These show that the faster the rate of climate change the greater the impact. This is a powerful signal that we can influence the impact of climate change in the future if we reduce the rate of carbon emissions and hence warming.”


Professor Nigel Arnell of the Walker Institute, University of Reading, said:

“The latest IPCC report on impacts, adaptation and vulnerability is a massive achievement. It has had to summarise scientific information from an incredibly wide range of scientific disciplines. Much of this information relates to potential impacts and responses at the local scale, and drawing global scale conclusions is very challenging. Climate change can affect individuals, organisations, societies and ecosystems in many different ways. I have been privileged to have been part of this process, as an author of the water chapter, and it has been a really stimulating experience.

“The report shows that climate change can have potentially very large impacts in many parts of the world and across many sectors – water, food, health, along the coast and in cities. It also shows two things relevant to how we cope with climate change. First, it shows that if we reduce emissions of greenhouse gases, then we can reduce the impacts we can expect at the end of the century – but we do not eliminate them.

“Second, our estimates of impacts at a particular place can be very uncertain, and this makes adaptation challenging. But another key conclusion of the report is that many more organisations are already seeking to adapt to future climate change – partly based on their experience of recent events – and that we know a lot more about how to apply risk-based approaches to dealing with climate change risks alongside other types of risk. The UK is very well placed here. We have good assessments of potential impacts through the Climate Change Risk Assessment and, through many years of effort by UKCIP[1] and more recently the Environment Agency, we have a toolbox of methods which organisations are beginning to use to manage their exposure to climate change risks.

“The IPCC report is a great summary of what we know about potential impacts of climate change and how we can cope with them. It also highlights were we need to learn more. For example, we still don’t really know that much about how climate change will manifest itself over the next few decades: we need to build on the new science of decadal forecasting discussed in the Working Group I report. And whilst we know that many organisations are seeking to adapt, we don’t really know how effective these adaptations will be and what information is really needed to help adaptation. “


Dr Stephen Thackeray, Lake Ecologist and Modeller at the Centre for Ecology and Hydrology (CEH), said:

“The second report of the IPCC fifth assessment capitalises upon the increasing body of evidence that climate change has already had an effect upon wild plants and animals, and the wider ecosystems within which they interact. The report makes it clear – these effects may be complex because ecosystems respond to the interactive effects of a changing climate and other stressors, such as habitat modification and pollution.

“It is clear that we need to understand, and plan for, these interactive effects if we are to successfully manage the natural world under ongoing climate change.”


Dr Sally Brown, University of Southampton and Tyndall Centre for Climate Change Research, said:

“With rising temperatures and other climatic and non-climatic threats there is an additional environmental risk, such that extreme event today may happen more frequently. This will be most felt in those ecosystems or regions which are already very vulnerable to change, such as coral reefs or small islands: The adverse impacts of climate change will not be evenly spread and will often exacerbate existing issues. This report iterates what we have learnt since AR4, that unless we act, adverse impacts will still occur. Where we can adapt to climate change and sea-level rise, we can increase resilience and reduce risk. The challenge is the effectively manage this process, taking account the multiple causes environmental change.

“Difficult decisions need to be made regarding adaptation. At times, these may cost more in the short term, but aim to provide long-term benefits and reduce risk. Thus, it is important to strategically plan for long-term benefits, whilst taking short-term needs in mind, and this is a challenging goal. This type of planning is starting to emerge. We still have a chance to reduce the adverse impacts of climate change, either by mitigation or adaptation, and we should take the opportunity to do so. Further research needs to bring together policy makers from global, national and local scales to achieve this version.

“This report indicates that on the coast, adverse impacts are also influenced by socio-economic issues, such as rapidly growing populations. How societies evolve and respond to any type of coastal change is therefore important, and decisions ideally need to be made collectively with multiple stakeholders and at different government levels.”


Prof Jeffrey S. Kargel, Department of Hydrology & Water Resources at the University of Arizona, said:

“The IPCC Working Group II report on Impacts, Adaptation, and Vulnerability includes an accurate high-level assessment of the worldwide and region-by-region changes—dominantly shrinkage—occurring to the world’s glaciers.  The report correctly attributes those changes mainly to climate change.  In my research field it is known that climate change is causing mountain processes—such as landslides, glacier lake outburst floods, monsoon-driven floods, and debris flows—to change in intensity, frequency, and location. The shifting mountain hazard picture and the necessary adaptive strategies are not captured in detail in this report but the high-level, broad issues identified apply to mountain hazards.  Details vary regionally, and the report captures that fact.

“A poignant and also accurate and troubling point raised in the report is that well-intended adaptive responses to climate change to reduce short-term dangers can be maladaptive.  To take an example drawn from my own work, in villages dotting many high mountain valleys an over reliance on development of warning systems or flood control systems to aid people living vulnerably on river flood plains can lend a false sense of security.  If these systems are not paired with other measures to reduce exposure and vulnerability, then the risk situation may grow.  Simply having a warning system installed to deal with certain types of floods, for instance, may increase the desirability and sense of security of living in such places on harm’s edge, thus further increasing exposure as vulnerable communities grow and people move into the more hazardous niches.  Further protective measures may not only be expensive but may plant the seeds of immense future tragedy when such systems are eventually overwhelmed, as they will be in some cases. 

“There are places on the Earth’s surface that are simply not safe to inhabit, and within vulnerable communities there are more dangerous and less dangerous spots.  My experience with mountain communities is that people often do not recognize that a small shift of location can make the difference between moderately but acceptably dangerous and exceptionally foolhardy.  This is a problem in poor developing countries such as Nepal, and it’s a problem in wealthy developed nations such as the U.S., as the Washington state community of Oso just discovered with a great tragedy.”


Prof Sir Andy Haines, London School of Hygiene and Tropical Medicine and a Review Editor of AR5 Chapter 11: Human Health

“The IPCC report identifies a number of key risks relevant to human health. These include increased risk of death during periods of extreme heat and reduced labour productivity due to increased thermal stress in vulnerable populations. Threats to health and livelihoods arise from increased flooding in coastal areas in small islands and also due to inland flooding in some areas. Of particular concern is the increased risk of under nutrition resulting from diminished food production in poor regions.

 “The risks of severe and irreversible impacts are increased as the magnitude of warming increases. For example in the high emission scenario (RCP 8.5), by 2100 the combination of increased temperatures and humidity is projected to compromise normal human activities such as working outdoors for parts of the year in some areas. Many strategies that reduce emissions of climate active pollutants (and thus the rate and magnitude of climate change) can result in large benefits to health, for example from reduced air pollution from shifts to cleaner energy sources. Protecting and improving health should be a major focus of efforts to address the challenges posed by climate change.”


Prof Nicholas Stern, Chair of the ESRC Centre for Climate Change Economics and Policy and the Grantham Research Institute on Climate Change and the Environment at London School of Economics and Political Science, said:

“This comprehensive report lays out very clearly the evidence that climate change is already having many impacts across the world, ranging from effects on human deaths from extremely hot or cold weather, crop yields, the availability of water from shrinking glaciers, and the distribution of plant and animal species. These are all happening after less than 1 centigrade degree of global warming.

“While people in all countries will need to make themselves more resilient to those impacts that cannot now be avoided over the next few decades, the potential risks from unmitigated climate change towards the end of this century and into the next will be very severe, particularly if global warming exceeds 2 centigrade degrees. The report warns that, during this century, climate change will increase the risk of human populations being displaced to escape shifts in extreme weather, such as floods and droughts, as well as relatively slow-onset impacts, such as desertification and sea level rise.

“This report presents a stark case for sharply reducing emissions of greenhouse gases to avoid potentially catastrophic impacts, such as the irreversible melting of the Greenland ice sheet and the resultant rise in sea level, to which we will not be able to make ourselves fully resilient and which lie outside the evolutionary experience of modern Homo sapiens.”


Prof Sam Fankhauser, who was a contributing author to AR5 Chapter 17: Economics of Adaptation and who is Co-Director of the Grantham Research Institute on Climate Change and the Environment and Co-Deputy Director of the ESRC Centre for Climate Change Economics and Policy at the London School of Economics and Political Science, said:

“The report documents how countries are already making themselves more resilient to the impacts of climate change, but much more needs to be done. In the UK and the rest of northern Europe, we will need to cope with increasing risks from coastal and inland flooding, heat waves and droughts. The UK and all rich countries must also provide significant support to help poor countries, which are particularly vulnerable, to cope with the impacts of climate change.”


Professor Georgina Mace FRS, Chair of the Royal Society Working Group on Human Resilience to Climate Change and Disasters said:

“The WG2 report builds on the WG1 report issued last year. WG1 showed strong evidence for anthropogenic climate change and how this could unfold over this century. Climate change matters to people and societies primarily through the impacts it has on the environment and the weather, especially the intensity and variability over time of changes to heat and rainfall, and the impacts these have on our life support systems – a secure supply of food and freshwater, good health, security of life and livelihoods. This report examines these risks in order to support policy-making to reduce them.

“Early, proactive adaptation is likely to be more effective than later, reactive responses and more likely to enhance resilience as well as reducing risk. Because we are not well adapted now, dealing with current crises in an incremental manner may distract from making the substantial changes to infrastructure, food, water and energy systems that will be necessary. Also, in an uncertain environment, being able to learn while doing may be safer and cheaper, and reduce the risks of maladaptation. Enhancing resilience – the ability to withstand future shocks and stresses – is a step beyond adaptation and especially important to reduce the widening variation in risks and opportunities for people in different areas of the world. Recent progress in development in parts of Asia and Africa could stall if risks to large numbers of poor and vulnerable people are not averted.”


Professor Paul Bates, member of the Royal Society Working Group on Human Resilience to Climate Change and Disasters said:

 “This new report makes clear that the effects of climate change over the coming decades will be far reaching and will affect almost every aspect of our lives from food production, health, the economy to the environment. At the same time a growing global population that is increasingly urbanized and interconnected is making society more vulnerable and less resilient. There is also good evidence that climate-related hazards hit those living in poverty the hardest.

“A very important point made by the report is that reducing our exposure to current climate threats is a critical first step towards mitigating or adapting to future climate change. Current climate and its variability already pose very significant risks, of which the recent UK floods are a clear example. Coping with current threats is actually the first step in preparing for the future. We have good evidence that spending on disaster prevention is much more cost effective than spending on disaster clean up. This is a classic ‘no regrets’ strategy that can improve livelihoods and well being now and in the future.

“Whilst there are uncertainties associated with future climate change impacts, this report demonstrates an overwhelming scientific consensus about what we do, and do not, know well. Good statistical tools now exist to characterize uncertainty in future climate projections and to take optimal decisions given this imprecise knowledge. We are moving to a situation where we know more about future climate changes than we do about possible future societal changes and their impact on vulnerability, and that this needs to be a focus of work in the coming years.”


Dr Bhaskar Vira, member of the Royal Society Working Group on Human Resilience to Climate Change and Disasters said:

“One key message from this Report is that the consequences of climate change will be very unequally distributed across the planet, with impacts likely to enhance the vulnerability of the most marginalised groups. The risks are particularly acute for those who are already in poverty, and will further undermine already stressed livelihood options for these populations, increase their exposure to hazards and negatively impact food security.

“The debate over climate change has to be sensitive to these distributional issues, as a focus on aggregate outcomes at a global scale usually hides these differentiated impacts. Our moral compass needs to focus on the injustice that results from the unequal exposure of people around the world to the risks of climate change, caused by the actions and lifestyles of those at the opposite end of the income distribution (both in their own countries, and internationally).

“A major collective effort from decision makers acting at local, national and global scales is needed to address the grossly unfair allocation of resources in relation to adaptive capacity, and the lack of adequate social protection and insurance measures in those parts of the world that have the largest populations at risk.”


Prof Robert Nicholls, University of Southampton and Review Editor of Chapter 5 Coastal Zones and Lowlying Areas, said:

 “The AR5 report reaffirms the large threats associated with climate change, and better identifies the importance of and need for both adaptation and mitigation responses than earlier IPCC assessments. In the future we need to understand these responses much better at global, regional and local scales.

“The report reaffirms the importance of coastal zones as a hotspot for climate impacts. Climate adaptation for coasts has grown significantly over the last few years, and these efforts need to further developed in the coming decades.”


Simon Potts, Professor of Biodiversity and Ecosystem Services at the University of Reading, said:

“A changing climate is just another problem for our already overburdened bees. Shifting seasonal patterns means bees are emerging earlier in the year, before enough flowering plants are in bloom to feed them. It’s like waking up to find breakfast is not served for another week.

“New climate patterns also means habitats are shifting, but bees can’t necessarily move as easily, especially as populations are already disjointed by modern land use.

“Some of our native bumblebees are already under threat of local extinction. Unless we begin to see the value of maintaining our natural environment, and understand the damage that we are inflicting on it, then we are storing up trouble for the future. Climate change is just one of the problems facing bees, and bees have enough problems as it is.

“If policymakers want one reminder of a potential victim of climate change, they need look no further than their own gardens – and the contents of their kitchen cupboards.”


Dr Hannah Cloke, a hydrologist at the University of Reading, said:

“The dredging of ‘pinch points’ along some river channels in the Somerset levels will help to speed up the flow of the water, and could help to move water downstream more quickly, easing the risk of localised floods. This action is supported strongly by residents and farmers, and is being carried out after the Prime Minister made specific promises that dredging would resume in the area.

“The government’s overall plan to alleviate flooding would help the Somerset Levels, but only a fraction of the £100million needed has been pledged so far by different branches of government. When money is tight, it’s important that funds are spent wisely to protect homes, businesses and farmland. Dredging is a costly, short-term solution, and I have serious doubts that this is the best way to prioritise action, compared to other longer-term solutions.

“Today’s report from the IPCC shows how risks from extreme rainfall and flooding are likely to change in the future. With increasingly difficult decisions ahead about which areas to protect, it’s important that we make sound, long term decisions based on solid evidence, not electoral cycles.”


Dr Rachel Warren, from the UEA-based Tyndall Centre for Climate Change Research and school of Environmental Sciences, and co-ordinating lead author of Chapter 19: Emergent Risks and Key Vulnerabilities, said:

“Global temperatures have already risen by 0.8C. If we do not take action to reduce carbon emissions, global temperatures could rise by 3-6C by the end of the century.

“WGII shows that the 0.8C rise we have already experienced has impacted agriculture and ecosystems.

“If temperatures rise by 2C, there will be further impacts to ecosystems, increased levels of extreme weather and problems for crop yields and water supplies.

“If temperatures go above 2C, we will risk melting of the Greenland ice sheet and other large scale changes. By 4C there will be a high impact on global agriculture, water resources and ecosystems, and a high risk to the Greenland ice sheet. Most world regions will be affected.

“The worrying thing is that our ability to adapt to these impacts is limited. What we need to do is act fast to reduce emissions of greenhouse gases like CO2. If we do this, we can avoid a large proportion of the impacts.

“Unfortunately we have left it too late to rely on reducing emissions alone and we cannot avoid all of the impacts. Some adaptation will be needed. But acting swiftly to reduce CO2 emissions will make adaptation easier. It will be necessary to reduce our emissions and invest in adaptation to avoid most of these climate change impacts.”


Prof Corinne Le Quéré, director of the Tyndall Centre for Climate Change Research at UEA

“This is not just another report, this is the scientific consensus reached by hundreds of scientists after careful consideration of all the available evidence.

“The human influence on climate change is clear. The atmosphere and oceans are warming, the snow cover is shrinking, the Arctic sea ice is melting, sea levels are rising, the oceans are acidifying, some extreme weather events are on the rise, ecosystems and natural habitats will be upset. Climate change threatens food security and world economies.

“We need rapid and substantial cuts in carbon emissions and a move away from burning fossil fuels if we are to limit global climate change below two degrees and mitigate these impacts.”


Dr Sally Brown, Research Fellow in coastal science and engineering at the University of Southampton, said:

What are the threats and what would be the cost?

“In recent years there has been an increasing recognition that coastal change is not all about climate change and sea-level rise, but other natural or man-made processes, population and economic growth are responsible too. Multiple threats can occur in one location. As such, any adaptive response to single or multiple impacts must include all factors influencing coastal change. Awareness to the adverse effects of climate change and sea-level is increasing.

“Vulnerable coastlines are already subject to saltwater intrusion, flooding, erosion and changes in wetlands. Sea-level rise will locally exacerbate these problems. Additionally, human pressures, such as population growth, particularly in cities, could lead to greater groundwater withdrawal, which can result in local land subsidence, thus worsening the problem. Without adapting to sea-level rise and extreme events, rising sea levels could have major implications of millions of people worldwide, cost billions of pounds of damage to urban environments and infrastructure and have an adverse effect on the natural environment affecting agriculture and wetlands.”

Where are the greatest risks?

“Risks are considered highest in south, south-east and east Asia (due to low-lying land, particularly deltas and large populations), and many parts of Africa and small islands (due to reduced capacity or capital to adapt, remoteness or access to appropriate resources). Throughout the 21st century, if we did not adapt, impacts from extreme could worsen not just due to sea-level rise, but also due to increased coastal population, economic growth and assets. However, the risks to the coast as so high that we do expect adaptation to occur. Globally, there is also concern that locally ocean pH is decreasing leading to ocean acidification. This, along with local changes to sea surface temperatures could lead to coral bleaching and changes to underwater ecosystems.”

What has been the response of scientists?

“Since 2007 and the IPCC’s Fourth Assessment Report scientists have a better understanding of how to adapt to sea-level rise, both at local and national levels. Scientists are better understanding multiple impacts at one location, which allows for more appropriate adaptation. Adaptation is happening more innovatively and at longer timescales, making scientists and engineers more prepared for adverse effects of climate change. This may include raising infrastructure or working with nature by selectively removing defences allowing space for water and increasing biodiversity – an engineering technique called managed realignment.”

What is happening in the UK?

“In the UK, through the Thames Estuary 2100 project, the Environment Agency and other organisations have determined how best to project to people of London and the surrounding area from flooding via adaptation, as the Thames Barrier (completed in 1982) has a limited lifespan. Taking global and national projections of sea-level change together with other environmental factors, they are strategically planning recommendations and actions to reduce flood risk over short (2010-2035), medium (2035-2050) and long-term (2050-2100) timescales. This adaptation planning is a little like a road map, in that you have one destination (e.g. 1m of sea-level rise), but a number of routes to reach it can differ (e.g. raise defences, flood storage, new barrier). By strategically planning multiple and flexible adaptation routes, this increases preparedness and reduces long-term risk, and thus economic costs. This kind of adaptation planning is new and innovative, and is increasing in popularity.”


Dr Jeff Price, of the UEA-based Tyndall Centre for Climate Change Research and school of Environmental Sciences

“The IPCC process is incredibly rigorous and involves hundreds of world-leading scientists and reviewers, multiple times, from around the world. It is the culmination of four years’ work and takes into account thousands of papers to produce a scientific consensus on climate-change impacts, adaptation, and vulnerability.  The findings are a review of the peer-reviewed literature and, as a consensus document it may be alarming, but cannot be alarmist.  This is especially true of the Summary for Policymakers (SPM) which is meticulously (line-by-line) reviewed by the Governments in a Plenary session.

“Our research shows that climate change could greatly reduce the diversity of even common plant and animal species around the world. Loss of global-scale biodiversity would significantly impoverish the biosphere and the ecosystem services it provides. There would also be a knock-on effect for humans because these species are important for things like water and air purification, flood control, nutrient cycling, and eco-tourism.

“The good news is that swift action to reduce CO2 and other greenhouse gases could prevent this biodiversity loss by reducing the amount of global warming and buying time for plants and animals to adapt.” 

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