Geology for Global Development

EGU Guest blogger

This guest post was contributed by a scientist, student or a professional in the Earth, planetary or space sciences. The EGU blogs welcome guest contributions, so if you’ve got a great idea for a post or fancy trying your hand at science communication, please contact the blog editor or the EGU Communications Officer Laura Roberts Artal to pitch your idea.

The Impacts of Climate Change on Global Groundwater Resources (Part 3 of 4)

barry-christopherChristopher Barry is a doctoral researcher at the University of Birmingham. He has written for the GfGD Blog in the past – detailing his contribution to water projects in Burkina Faso and fundraising efforts to support such work. We have recently added a briefing note to our website, written by Christopher, describing the role of climate change on global groundwater resources. You can access the full briefing note here.

To help share the contents of this briefing note we are publishing a portion of it’s contents over a series of four blogs. In this third instalment we focus on the effects of temperature and precipitation changes on groundwater recharge. At the end of each blog is a link to the full PDF, where you can read each section in its full context and find a full reference list.

4. Temperature Changes: Effects for Groundwater Recharge

4.1 What Happens

Groundwater recharge occurs by rainwater infiltrating through the soil.  Water at the surface will either enter the soil and groundwater, evaporate, run off into rivers and the sea, or be consumed.  The atmospheric rise in temperature increases the amount of surface water being evaporated, and therefore reduces the amount of water available for groundwater recharge.

In basins in which the groundwater is recharge from melting ice, the rise in temperature increases the rate of recharge by increasing the rate at which the ice melts.  But eventually the ice becomes depleted and then that source of water is lost.

4.2 Example

Tajikistan, in Central Asia, is a country that is highly dependent on melt water from glaciers as a source of water.  In the Pamir mountains of Tajikistan, a retreat of glaciers due to melting of 1% per year has been observed.  This raises concerns about the long-term security of this water resource.  In the short-term, increased rates of melting poses the risk of large outbursts of water.  Such an event occurred in 2005, killing 25 people (Mergili et al., 2012).

5. Precipitation Changes: Effects for Groundwater Recharge

5.1 What Happens

Climate change focuses the rainfall across the year into a shorter, more intense wet season.  In humid and temperate areas, much of the intense rain water may be wasted into the sea, because the soil has a limited capacity for infiltration.  In these areas, intense rainfall caused by climate change is likely to overwhelm the process of infiltration and therefore reduce annual groundwater recharge.

Conversely, in the arid and semi-arid climates of the sub-tropics, recharge is favoured by intense rainfall.  This is because rain water falling at a slower rate is likely to be largely evaporated.  More intense rainfall is too fast for a large proportion of rainwater to be evaporated, so a lot more of the water is able to infiltrate.

These factors are demonstrated in Figure 2.

GWater3

For basins containing ice or glaciers, the type of precipitation is also important.  Rising temperatures increase the amount of rainfall relative to snowfall.  The effect of intense rainfall is reduced if some precipitation falls as snow, because the run-off is delayed until the snow melts.  Therefore a reduction in snowfall compared to rainfall also increases the intensity of wet season run-off.

5.2 Example

In the UK, a set of climate change projections developed by the Meteorological Office called UKCP09 [1] have been used to assess the likely outcomes of changing climate on water resources.  UKCP09 consists of eleven equally likely climate scenarios projecting the next 150 years.  Simulations of river flows consistently show that we should expect a decrease in mean flow rates and even lower flows during droughts, although there is variability in the predicted results for high flow events.  Conversely, the effect on groundwater level is less pronounced – though for the UK a general decrease is more likely, some climate projections would give an increase with some groundwater models.

[1] http://ukclimateprojections.metoffice.gov.uk/21678

Download the full briefing note (including a reference list) on the Water and Sanitation page of the GfGD website. The final instalment, Part 4, will be published on this blog soon.

The Impacts of Climate Change on Global Groundwater Resources (Part 2 of 4)

barry-christopherChristopher Barry is a doctoral researcher at the University of Birmingham. He has written for the GfGD Blog in the past – detailing his contribution to water projects in Burkina Faso and fundraising efforts to support such work. We have recently added a briefing note to our website, written by Christopher, describing the role of climate change on global groundwater resources. You can access the full briefing note here.

To help share the contents of this briefing note we are publishing a portion of it’s contents over a series of four blogs. In our last blog we gave an introduction to key impacts. In this latest blog we focus on the issue of saline intrusion. At the end of each blog is a link to the full PDF, where you can read each section in its full context and find a full reference list.

3. Saline Intrusion

3.1 How it happens

Fresh (non-saline) groundwater in coastal areas forms an interface with saline groundwater under the sea.  Fresh water is less dense than saline water, so it will be found above the saline water.  Fresh water and saline water also do not tend to mix.  Both these effects are good because it means that the fresh water is easily accessible and will not be contaminated by the adjacent saline water.  The fresh groundwater discharges into the sea and may be used by humans.  It is replenished by recharge from rainfall (however indirect that may be).

This balance of input and output can be taken out of balance.  Excessive use of groundwater will increase the output, and so cause the saline-fresh water interface to move inland.  The system is also taken out of balance by a rise in sea-level, which will cause the rate of fresh water discharge into the sea to increase, until the fresh-saline water interface has moved up and inland.  As a result of this, wells drawing in freshwater near the interface may start to draw saline water (Figure 1).

GWaterBlog2

Global sea-level rise is expected as a result of melting ice near the Earth’s poles, which increases the amount of water in the sea and thermal expansion of water due to heating.  Both effects are driven by rising atmospheric temperature.  It was estimated that global average sea-level rose by about 3 cm between 1993 and 2003 (IPCC, 2008), with roughly equal contributions from melting ice and thermal expansion.

3.2 Threatened Areas

Coastal areas are the main source of concern for these effects due to the number of large cities on the coast across the world.  Large delta areas are particularly vulnerable, with large areas of flat land in danger from inundation, which, as well as many other problems, would make all the groundwater under the flooding salty.  Inland aquifers surrounded by saline aquifers may also come under threat as the freshwater recharge to them is decreased by changes in rainfall patterns and an increase in evapotranspiration (direct evaporation and evaporation from uptake through plants) of surface water.

Small oceanic islands are particularly vulnerable to saline intrusion because their freshwater lens by buoyancy and the balance between recharge and outflow.  The Ghyben-Herzberg relationship demonstrates, by considering buoyancy, that the freshwater lens will extend to a depth below sea level forty times the height by which it stands proud of sea level.  Therefore a small rise in sea level will be cause a decrease in the depth of the freshwater lens by approximately forty times its magnitude.

3.3 Examples

There is 4000 square kilometres of low-elevation land in the Nile Delta that is thought to be in danger of being submerged under the sea because of sea-level rise in the Mediterranean within this century.  All fresh groundwater resources under this area would be lost if this were to occur (Sherif and Singh, 1999).  In addition, a rise in sea-level relative to the groundwater table would cause in intrusion of saline water landward of the shore, depending on the magnitude of the rise.  A sea-level rise of 0.2 m would cause a landward intrusion of the saline-fresh water interface by about 2 km, according to the hydrogeological computer simulations of Sherif and Singh (1999).  In an inland aquifer case, Chen et al. (2004) note that regional climate change leading to reduced groundwater recharge (discussed in a later section) to a freshwater aquifer in Manitoba, Canada, could result in an intrusion of salt water from an adjacent saline aquifer because of the resulting water pressure difference.

Saline intrusion is also caused by high abstraction of groundwater for human consumption because it causes a fall in the water table relative to sea-level.  With increasing global population and strain on surface water resources, which in many ways are more sensitive to climate change than groundwater, saline intrusion caused by groundwater abstraction is likely to occur in parallel with saline intrusion caused by sea-level rise, and it is difficult to separate the separate drivers to intrusion from observations.

Download the full briefing note (including a reference list) on the Water and Sanitation page of the GfGD website. Parts 3 and 4 will be published on this blog in the coming days.

The Impacts of Climate Change on Global Groundwater Resources (Part 1 of 4)

barry-christopherChristopher Barry is a doctoral researcher at the University of Birmingham. He has written for the GfGD Blog in the past – detailing his contribution to water projects in Burkina Faso and fundraising efforts to support such work. We have recently added a briefing note to our website, written by Christopher, describing the role of climate change on global groundwater resources. You can access the full briefing note here.

To help share the contents of this briefing note we are publishing a portion of it’s contents over a series of four blogs (i) Introduction to Key Impacts; (ii) Saline Intrusion, (iii) Effects for Groundwater Recharge of Temperature and Precipitation Charges, and (iv) Effects for Groundwater Recharge of Near Surface Turbidity and Parched Soil/Vegetation. At the end of each blog is a link to the full PDF, where you can read each section in its full context and find a full reference list.

Introduction

Over the last two centuries, the content of the Earth’s atmosphere has changed, with certain gases, known as greenhouse gases, increasing significantly in concentration.  Carbon dioxide, the most abundant of these, has increased in concentration by about 50%.  They are termed “greenhouse gases” because of their effect of trapping heat in the Earth’s atmosphere rather than allowing it to be radiated into space, in the same way that a greenhouse traps heat inside of itself.  This greenhouse effect, is necessary for life on Earth, because without it the Earth would be too cold to hold liquid water.  However, due to the unnaturally rapid increase in greenhouse gases, the Earth’s atmosphere is heating at a rate fast enough to unbalance many of the Earth’s climates, ecosystems and ice formations, which gives rise to the term climate change.  These changes have profound impacts on the Earth’s water resources.  This section outlines some of the main threats posed by climate change to groundwater resources across the globe.

The effects of climate change on groundwater are slower than those on surface water.  This gives an advantage for areas trying to adapt to the impacts of climate change on their water resources, in that they have more time.  But groundwater is susceptible to depletion and degradation, so an awareness of the threats posed to groundwater by changing climate is important in long-term planning of water resources for communities.  There are cases where people’s activities may be adjusted to minimise the potential impacts of a threat, such as disposing of waste away from water sources, in light of the increased risk of floods and high river levels.  In other cases, it is useful to be able to predict where groundwater is going to come under unavoidable threat and therefore the limitations of an aquifer’s reliability in the future.  For example, a coastal community relying on an aquifer which is under threat from intruding salt water due to sea-level rise would be wise to limit its development of near-coastal groundwater resources for its water supply.

2. The effects of climate change that relate to groundwater

There are two large effects of climate change that are thought to have serious implications for groundwater resources, by a number of processes.

2.1 Change in temperature

The Intergovernmental Panel on Climate Change (IPCC) in 2007 estimated that the average temperature across the globe had risen by about 0.7 °C over the 19th century, with an accelerating rate of warming (Trenberth et al., 2007).  The temperature has implications for ice, at the poles and in glaciers, and evaporation of water at the surface.

2.2 Change in precipitation

Seasonal rainfall patterns have been observed to change, as a general trend.  Trenberth (2011) explains that the increase of the temperature of the air increases its capacity to hold water vapour, by 7% for every 1 °C.  Therefore, a greater amount of water vapour is required to form water droplets and hence precipitation and, conversely, there is more water available in the atmosphere during rainfall events, so these become more intense.  The result of this is that rainfall becomes polarised, both in time and in space.  That is to say that wet places and wet seasons become wetter and dry places and dry seasons become drier.

The overall effect is that wet seasons, or winters, are becoming shorter and more intense, while dry seasons are becoming more protracted.  The frequency of storms, floods and conversely droughts are set to increase.

Download the full briefing note (including a reference list) on the Water and Sanitation page of the GfGD website. Parts 2-4 will be published on this blog in the coming days.

Guest Blog: Exploring the Sustainable Development Goals at the University of Tübingen (Germany)

AuthorsSolmaz Mohadjer and Sebastian Mutz, University of Tübingen researchers, recently designed and facilitated a seminar on the topic of Geology and the Sustainable Development Goals. Below, they share some results from their pilot implementation at the University of Tübingen, Germany.

There is an African proverb that says “if you want to go fast, go alone. If you want to go far, go together.” The road set by the Sustainable Development Goals (SDGs) for the next 15 years is long and riddled with potholes. To travel far, everyone needs to join in and do their part. This includes the geosciences community. In October 2015, 130+ from the geosciences community gathered at the Geological Society of London to educate themselves about the SDGs and explore the role of the geosciences community in achieving them. At the conference, I spoke about the role of geohazards research and practice in addressing key sustainable development issues such as disaster risk reduction. The conference emphasized other sustainable development issues that are at the heart of many geoscience disciplines (e.g., sustainable agriculture, water and sanitation, and climate change). Once back in Tübingen, Sebastian Mutz and I created a plan for doing our part as geologists in addressing the SDGs. To hop on the road to the SDGs, we decided to go small and stay local. We designed and taught two sessions on the SDGs with the target audience being our own colleagues.

The curriculum can be downloaded and used for free:
Session 1: Curriculum instruction (PDF) and accompanying presentation (PDF)
Session 2: Curriculum instruction (PDF) and accompanying presentation (PDF)

These sessions are designed to give a brief introduction to the SDGs and the role of geosciences in achieving them. The curriculum is both lecture- and activity-based and can be easily adapted to suit participants from different backgrounds. The curriculum also provides participants with an opportunity to present their current/previous work in the context of the SDGs. The curriculum completion takes about 2 hours per session.

Below we describe an activity that was conducted as part of the second session. We then briefly state the key observations and our interpretation of them.

Inspired by a discussion session that was conducted as part of the 3rd Annual Conference of Geology for Global Development, we facilitated an interactive group activity in the second session during which participants were encouraged to think about how the SDGs should shape geosciences education, research, industry practice and engagement with civil society. Participants were given a series of questions related to the aforementioned categories and were asked to brainstorm and write down their responses on Post-it notes under each question. Participants were then asked to read and discuss all responses and indicate their level of agreement with each response. Red round stickers placed next to a response indicated their disagreement while green stickers showed their agreement (Figure 1).

IMG_20160119_140926

Figure 1. Participants’ responses on Post-it notes to questions and their level of agreement with each response using round stickers (red: disagree, green: agree).

The three key observations from this activity (as demonstrated in Figure 2) as well as our interpretation are:

  1. High level of participation shows that the participants believed the SDGs can and should shape geoscience education, research, industry practice and engagement with civil society. Participants who are all members of the geoscience community were able to generate suggestions as to how this can/should be done in each category. The large number of ideas generated during this activity highlights the potential and confirms the important role of geoscientists in achieving the SDGs.
  1. While participants were able to generate suggestions to questions listed in all categories, their level of engagement (as reflected by the number of suggestions) across all categories is uneven. This could reflect the background of this specific group of participants consisting of geoscience students and researchers with varying degrees of involvement with industry practice. Therefore, more suggestions pertaining to questions related to these fields (i.e., education, research, and industry practice) were generated. The total number of votes (both negative and positive) in these fields is also higher. This possibly indicates a higher level of confidence in participants’ opinions related to these fields which could be due to this same background. The few suggestions under the civil society category might highlight participants’ limited (or lack of) engagement with civil society (e.g., NGOs). Organizations such as Geology for Global Development are currently working to address this issue by equipping geoscientists with skills and knowledge needed for meaningful engagement in the development field.
  1. Participants seem to have opposing opinions as to how the SDGs should shape geoscience research. This is reflected by the high number of positive and negative votes received in this category. Within this category, participants agree on suggestions pertaining to the following questions: (1) how to better connect researchers with those working in development, (2) how to ensure research outputs are more accessible; and (3) how to facilitate more effective research partnerships globally. Popular suggestions often related to sharing technologies and improving science communication (e.g., open-source software, journals and online knowledge-sharing platforms) and making research partnerships with local institutions mandatory by funding agencies. However, all suggestions related to the researchers’ role in enhancing scientific research in developing countries received negative votes. These suggestions included: funding bi-lateral programs, creating positions that are related to specific developing countries (for example: the work of Institut de recherche pour le développment), and donating old (but still usable) equipment to local universities and research partners.

Taken all together, participants seem to recognize the importance of forming effective global research partnerships as a means of implementation for all the SDGs, and that innovative solutions for enhancing scientific research in developing countries should look beyond providing traditional technical assistance and support.

SDG_stats

Figure 2. Participants’ participation per discussion topic. Blue indicates the number of ideas generated per category, red indicates the number of negative votes received in each category; green indicates the number of positive votes received in each category. The numbers shown at the top of each column correspond with the number of ideas/votes per category. SDGs: Sustainable Development Goals.

The key point we hoped to convey during the seminar was to encourage our colleagues to think more broadly about their research findings and their role as researchers in solving global issues. “The seminar activities helped me realize why I should care about the SDGs and the applicability of my research to real world problems,” commented Dr. Karim Norouzi. The seminar was considered to be a great experience by Dr. Karl Lang. “[This is] something we should be doing regularly, but seminars like this help to stretch our thinking and consider new perspectives,” said Dr. Lang on the importance of thinking critically about the underlying motivations for scientific research. For others like Jessica Starke, the seminar was a good starting point for learning about the SDGs. “I recommend that the seminar be repeated for other students and members of the scientific community so that they are familiar with these important goals.”