Blog by Paul Drummond, UCL ISR Researcher

As is well known, the climate system and hydrological cycle are inextricably linked. A warmer atmosphere melts water stored as ice at high latitudes and altitudes leading to sea level rise, which in turn allows more of the sun’s radiation to be absorbed, further accelerating warming. A warmer atmosphere is able to hold more moisture, increasing the frequency of heavy rainfall events in areas of previously moderate conditions, whilst shifting climatic zones may either reduce the intensity and timing (or even remove) heavy rainfall in areas that rely upon it. Water vapour itself, of course, is the most prevalent greenhouse gas.

Might it be this relationship that eventually spurs the world into action to reduce emissions to prevent the worst effects of a changing climate?

It certainly seems possible. The recent drought in California and flooding in the south of England have both bumped climate change to the top of the political agenda in the USA and UK once more. The current Californian drought has so far lasted for nearly three years, with 2013 the driest year since records began. Reservoir levels are dangerously low, with fires running rampant across the parched landscape. The large agricultural economy has been hit extremely hard. The situation in the south and particularly south-west of the UK couldn’t be more stark. England and Wales saw the most winter rainfall since 1766, bursting river banks and overcoming defences to flood over 6,500 homes and around 50,000 hectares of farmland.

These opposing sides of the same coin directly impact the lives and livelihoods of people living and working in these areas. Naturally, they seek reasons for why this is happening to them, who is at fault, and assurances that all efforts will be taken to make sure that it does not happen again.

At least some of blame has been focussed on government policy. In the UK, a lack of dredging of rivers and inadequate historic investment in flood defences has been blamed, along with long-term trends of removing upland vegetation for pasture and expanding settlements onto floodplains (or even reclaimed land in the case of the Somerset Levels). Of course, these aspects all combine to a greater or lesser extent to produce the damage experienced. But such factors may only control what happens to precipitation once it has occurred, and not the volume that must be dealt with.

This is where climate change enters the present discourse. Of course, an explicit link between these specific extreme events and climate change cannot be drawn, however a changing climate is likely to increase the frequency by which these events occur, and their intensity when they do. Despite this, both President Obama and David Cameron have voiced their opinions that climate change very much had a role to play in recent events (or in Cameron’s words, ‘very much suspects’). Such rhetoric, particularly in the UK from a government who it was felt were abandoning their ‘green’ credentials over time, reflects the extent to which climate change, and whether and how we should tackle it, has re-entered the public debate.

Of course, the USA and UK are not the only states in which water issues can be prevalent. In many countries, the absence or abundance of water is of paramount importance – a concern this is only likely to increase over time. However, it appears that developing nations are over-represented among this number. For example, small island states and low-lying countries such as Bangladesh are likely to be the first victims of a rising sea level, whilst the nations of the North Africa are likely to be among the first to feel extended periods of chronic water shortages, in parallel to expected rapid increases in population.

Unfortunately, these are not the nations that hold the key to meaningful global climate action, and they broadly do not have the financial resources to adapt to their new climate regimes if such action is not taken. It is the developed nations, along with the BRICS, which are pivotal. It is only when these countries decide that mitigation action is indeed necessary that significant steps will be taken, and this is unlikely to happen until climate change ceases to be an abstract concept in the mind of the general populous, but a real and present issue – with the most likely manifestation of this to be when previously extreme flood and drought events become increasingly normalised.

Blog by Simon Damkjaer, UCL ISR PhD student

Substantial increases in the combustion of fossil fuels over the 20th Century have led to a shifting climate, whose impacts on global water resources are best experienced through changes in the global hydrological cycle.  As part of a series of posts related to the 2013 UCL Energy and UCL ISR Climate Week, this blog post provides an overview of the most direct impacts of climate change on water resources and highlights my Doctoral Research on the importance of hydrological stores under a changing climate.

Ice sheets and glacier retreats
Climate change has been popularly coined “Global Warming”, and as the name itself suggests, means rising temperatures.  The first way, in which rising temperatures impact global water resources is through the transfer of freshwater from a state of solid snow and ice into water as a fluid state.  The ice-sheets of Greenland and Antarctica have been melting at alarming rates over the past decades [1], which has led to an increase in the mean rate of sea-level rise of 3.3 mm/year relative to a 20th Century average of 1.7 mm/year [2].  The effects of rising sea levels, simply put, will exacerbate the risk of storm surges at coastal areas.

Furthermore, snowfall over the polar ice-sheets is predicted to be reduced.  This, in combination with melting ice-sheets, will decrease the ice-sheets’ albedo effect – that is the amount of surface that deflects incoming solar irradiation.  A reduction in albedo effect risks triggering so-called feedback mechanisms, a system of circular loops, in which the warming of the global surface is enhanced, as less incoming heat is reflected due to a reduction in albedo which is caused by ice-sheet retreat due to rising temperatures and so forth.

Although alpine glaciers are currently melting at rates three times lower than that of ice-sheets, their impacts are still felt through effects on river flow, whose influence range from moderate in mid-latitude basins, to major influence in very dry basins.  The main issue related to an increase in glacier melt rate is that it causes a mismatch and unpredictability in the timing of dry period river flows, which has implications for access to water for agricultural purposes.

Precipitation, Evaporation and Transpiration alterations
The second way in which the global water cycle is affected by a shifting climate is experienced by the ability of hotter air to hold more water, which in return affects precipitation and evaporation rates.  The effects of increasing precipitation rates are felt at two extremes.  At the one end, rainfall events will be more extreme, short-term and variable, which will lead to increased run-off and thus higher flood risks.  At the other end, the intervals between these short-lived and heavy rainfall events, will get longer, which increases drought risks.
As temperatures rise, more water evaporates back into the air, which means less water availability for crops – “less crop per drop”.  Additionally, from a biological point of view, higher CO2 levels in the atmosphere, cause terrestrial plants to transpire less, thus lowering the amount of water they use – “less drop per crop”.    It, therefore, becomes evident that the impacts of climatic changes will have severe implications for food security in the future.

Uncertainty: a key challenge
The biggest challenge to the water resources community in modelling the impacts of a shifting climate on water resources is the extreme uncertainty associated with the exercise.  Apart, from the general well-known processes, how these shifts will affect water’s wider environmental interconnectedness still remains unclear.  In fact, the Intergovernmental Panel on Climate Change (IPCC) have taken a long time to properly include the effects of climate change on water resources into their annual reports, which is evidenced by only dedicating ten pages in their 4th Annual Report.  The reason for this has not been to downplay the importance of water, whose scarcity indeed was declared the second biggest global risk at the 2013 World Economic Forum, but simply because predicting the effects of climate change on water resources, continues to prove difficult, particularly on groundwater, where data is scarce.

The importance of stores
The effects of climate change on the global hydrological cycle may appear to only lead to situations of disadvantages.  However, studies from East Africa [3], which my Doctoral Research is grounded in, suggests that climatic effects in this part of the world, will cause an intensification in rainfall, which benefits groundwater recharge.  As research in the domain increases, so does the realisation that our understanding of groundwater resources remain limited.
Groundwater stores will become increasingly important in the future, as they possess a slower response-time to climatic shifts than that of surface water.  These resources, therefore, should be considered a key adaptation strategy to a shifting climate.  However, a history of legislative neglect of the resources, means that notions and understanding of sustainable management and utilisation of groundwater stores remain in their infancy.  Thus, it remains to be seen what the water the resources community has in store for the future.

[1] Rignot et al. (2011), Geophys. Res. Lett., vol. 38, L05503

[2] Nicholls and Casenave (2010), Science, vol. 328, 151 7-1520.

[3] Taylor et al. (2012) Nature Climate Change, Vol. 2, doi: 10.1038/nclimate1731

Blog by Nick Watts, Head of Project, UCL-Lancet Commission
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“Above all, be visionary – this Commission is designing integrated solutions to what has been described as the biggest global health threat of the 21^st century”. These were the parting words of Richard Horton – the editor of The Lancet – to the Commissioners at a recent London meeting.

The 2014 UCL-Lancet Commission on Climate Change and Health is an ambitious initiative bringing together senior international climate scientists, economists, energy experts, and health professionals to present mitigation and adaptation policies necessary to protect human health from climate change, and promote sustainable development. The Commission is truly interdisciplinary and international, consisting a tripartite collaboration between University College London, Tsinghua University, and the Stockholm Resilience Centre. Within UCL, the Commission is working across the Institute of Global Health, the Energy Institute, the Institute for Sustainable Resources, the Geography Department, and the Department of Science, Technology, Engineering and Public Policy. Presenting its work in February 2015, the commission will ultimately aim to be policy-relevant, taking an academic ‘honest broker’ approach where experts in areas relating to climate change use their knowledge to integrate scientific knowledge more cohesively with policy.

Published in the Lancet – arguably the most influential medical journal in the world – the Commission understands climate change as a ‘health emergency’. Its work is divided in to five working groups, each tackling a particular part of the policy response to this crisis, and tasked with producing a chapter for the final report. Over the next week, a post from each of the working groups should give you a better idea of what they’ve got planned. But in the meantime, here’s a brief summary of what they’re looking at:

1)     WG1 will set the stage by laying out the latest evidence in climate science and the impacts these global environmental changes are having on human wellbeing. The group will attempt to employ innovative methods to demonstrate how global patterns of vulnerability shift with environmental and demographic changes;

2)     In light of the scientific update above, section 2 will examine the most effective solutions to improve resilience in the most vulnerable communities. One area of particular interest being explored is with regards to identifying the limits to adaptation;

3)     Experts in energy and climate change mitigation will explore the emergency technical solutions available, prioritising them according to their cost-effectiveness, time to implementation, and feasibility. In particular, Commissioners in WG3 will explore the ‘epidemiology of energy policy’, looking at what happens when large-scale policy changes are implemented in practice.

4)     The fourth component of the report will discuss a broad range of alternatives to financing the defined technical solutions. They’re looking at a broad range of responses, including international trade, taxation (regressive and progressive), capital and bond markets, and investment incentives and penalties.

5)     The final section will bring together the above policy options, providing insight in to the political mechanisms necessary to trigger a cascade of technical and financial action.

The task ahead of the UCL-Lancet Commission is indeed ambitious, with more than 60 academics and experts from around the world working on it right up until early 2015. The key findings of our work will take some time to come to light, but if the last 12 months are anything to go by, the results of the Commission will most certainly “be visionary”.

From 3-9 March 2014, UCL Energy Institute and UCL Institute for Sustainable Resources staff and students will be blogging here daily to celebrate Climate Week 2014.

Topics will include:

• Climate and health
• Climate and poverty eradication
• Climate and water
• Climate and resources
• Climate and energy

We will also be publishing a series of blog posts, focussing on themes relating to the newly launched 2014 UCL-Lancet Commission on Climate Change and Health. The commission is an ambitious initiative bringing together senior international climate scientists, economists, energy experts, and health professionals to present mitigation and adaptation policies necessary to protect human health from climate change, and promote sustainable development. The Commission is truly interdisciplinary and international, consisting a tripartite collaboration between University College London, Tsinghua University, and the Stockholm Resilience Centre.

Topics will include:

• Climate Science & Health Impacts
• Resilience & Adaptation
• Energy & Technical Solutions
• Finance & Economics
• Political Mechanisms

Follow us on Twitter for regular updates on new blogs:

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