GeoLog

GeoLog

Geosciences Column: Africa’s vulnerability to climate change

Climate change is set to hit the nations of the Global South the hardest.

Ravaged by armed conflicts, a deep struggle with poverty, poor governance and horizontal inequality, some parts of Africa and other Global South regions are arguably the most vulnerable to the impacts of climate change. Largely reliant on natural resources for sustenance, current and future changes in temperatures, precipitation and the intensity of some natural hazards threaten the food security, public health and agricultural output of low-income nations.

Climate change increases heat waves across Africa

Among other impacts, climate change boosts the likelihood of periods of prolonged and/or abnormally hot weather (heat waves). A new study, by researchers in Italy, reveals that in the future all African capital cities are expected to face more exceptionally hot days than the rest of the world.

The new research, published in the EGU open access journal Natural Hazards and Earth System Sciences, has found that extreme heat waves affected only about 37% of the African continent between 1981 to 2005 while in the last decade, the land area affected grew to about 60%. The frequency of heat waves also increased, from an average of 12.3 per year from 1981 to 2005 to 24.5 per year from 2006 to 2015.

By merging information about the duration and the intensity of the recorded heat waves, the authors of the study were able to quantify the heat waves using a single numerical index which they called the Heat Wave Magnitude daily (HWMId). The new measure allowed the team to compare heatwaves from different locations and times.

Geographically plotting the HWMId values for daily maximum temperatures over five-year periods from 1981 to 2015, clearly showed there has been an increase, not only in the number of heat waves and their distribution across the continent, but also an escalation in their intensity (see the figure below). The trend is particularly noticeable since 1996 and peaks between 2011 and 2015.

Heat Wave Magnitude Index daily of maximum temperature (HWMIdtx) for 5-year periods of Global Surface Summary of the Day (GSOD) gauge network records from 1981 to 2015. The bottom-right panes show the spatial distribution of the GSOD station employed in this study. From G. Ceccherini et al. 2016 (click to enlarge).

The figure also highlights that densely populated areas, particularly Northern and Southern Africa, as well as Madagascar, are most at risk.

The rise in occurrences of extreme temperature events will put pressure on already stretched local infrastructure. With the elderly and children most at risk from heat waves, the health care needs of the local population will increase, as will the demand for electricity for cooling. Therefore, further studies of this nature are required, to quantify the implications of African heat waves on health, crops and local economies and assist government officials in making informed decisions about climate change adaptation policies.

Lessons learned from climate adaptation strategies

In the face of weather extremes across Africa including heat waves, droughts and floods, it is just as important to carefully assess the suitability of climate change adaptation policies, argues another recently published study in the EGU open access journal Earth System Dynamics.

Take Malawi, for instance, a severely poor nation: over 74% of the population live on less than a dollar ($) a day and 90% depend on rain-fed subsistence farming to survive. According to Malawi government figures, one-third of the country’s gross domestic product (GDP) comes from agriculture, forestry and fishing.  As a result, the country – and its population – is vulnerable to weather extremes, such as variability in the rainy season, prolonged dry spells and rise in the number of abnormally hot days.

A 2006 Action Aid report states that “increased droughts and floods may be exacerbating poverty levels, leaving many rural farmers trapped in a cycle of poverty and vulnerability. The situation in Malawi illustrates the drastic increases in hunger and food insecurity being caused by global warming worldwide.”

The Lake Chilwa Basin Climate Adaptation Programme (LCBCCAP) aims to enhance the resilience of rural communities surrounding Lake Chilwa to the impacts of droughts, floods and temperature extremes. The lake is a closed drainage lake (meaning it relies on rainfall to be replenished) in the south eastern corner of Malawi.

Perceptions of how climate change affects residents of the Lake Chilwa Basin. From H. Jørstad and C. Webersik, 2016 (click to enlarge).

The authors of the Earth System Dynamics study interviewed a group of 18 women (part of the LCBCCAP programme), back in early 2012, to understand how they perceived they were affected by climate change and whether the adaptation tools provided by the programme would meet their long-term needs.

The women agreed unanimously: climate in the Lake Chilwa Basin was changing. They reported that rainy seasons had become shorter and more unreliable, leading to droughts and dry spells. One of the women mentioned raising temperatures and fewer trees, due to overexploitation.

All those interviewed were part of the women fish-processing group, an initiative which sought to provide an alternative income for the women as traditional agricultural activities became unreliable due to erratic rainfall and prolonged dry seasons.

While the women’s new occupation did provide economic relief, the study authors highlight that the group’s new source of income was just as dependant on natural resources as agriculture.

Throughout the interviews, the women of the fish-processing group expressed concerns that the they thought Lake Chilwa might dry up completely by 2013.

“Yes, the lake will dry up and I will not have a business,” says Tadala, one of the women interviewed in the study. While another local woman said “Yes, lower water levels in the lake is threatening my business.”

Lake Chilwa has a long history of drying up: in the last century it has dried up nine times.  If the lake dried up completely, the women of the fish-processing group would be out of business for 2 to 4 years. Even small drops in the water level affect the abundance of fish stocks.

Lake Chilwa has a history of drying up. These Landsat images show the net reduction of lake area between October 1990 and November 2013. show changes to the extensive wetlands (bright green) that surround Lake Chilwa. These wetlands are internationally recognized as an important seasonal hosting location for migratory birds from the Northern Hemisphere. Credit: USGS

The interviews were carried out in early 2012. The previous two years had seen very limited rainfall. Not enough to sustain the lake, but the situation, at the time of the interviews wasn’t critical. However, throughout the summer of 2012 the lake water levels started falling rapidly prompting the relocation of large groups of lakeshore residents. Those dependant on fishing to support their families were most affected.

The women fish-processing group is a good demonstration of how local communities can adopt low-cost measures to adjust to climate change. At the same time, it highlights the need to assess climate adaptation strategies to take into consideration whether they too are dependent on climate-sensitive natural resources. The new research argues that diversifying people’s livelihoods might provide better long-term coping mechanisms.

By Laura Roberts Artal, EGU Communications Officer

References and resources

Ceccherini, G., Russo, S., Ameztoy, I., Marchese, A. F., and Carmona-Moreno, C.: Heat waves in Africa 1981–2015, observations and reanalysis, Nat. Hazards Earth Syst. Sci., 17, 115-125, doi:10.5194/nhess-17-115-2017, 2017

Jørstad, H. and Webersik, C.: Vulnerability to climate change and adaptation strategies of local communities in Malawi: experiences of women fish-processing groups in the Lake Chilwa Basin, Earth Syst. Dynam., 7, 977-989, doi:10.5194/esd-7-977-2016, 2016.

ActionAid: Climate change and smallholder farmers in Malawi: Understanding poor people’s experience in climate change adaptation, ActionAid International, 2006.

NASA: The consequences of climate change

United States Environmental Protection Agency (EPA): Understanding the Link Between Climate Change and Extreme Weather

National Oceanographic and Atmospheric Administration (NOAA): Heat wave, a major summer killer

Imaggeo on Mondays: Life on bare lava

Life on bare lava

There are plenty of hostile habitats across the globe but some flora and fauna species are resourceful enough to adapt and make extreme environments their home. From heat-loving ants of the Sahara to microbes living in the light-deprived ocean depths, through to beatles who brave the bitterly cold Alaskan winter, there are numerous examples of plants, animals and bugs who strive in environments often considered too challenging to harbour life. In today’s post, brought to you by geomorphologist Katja Laute, we feature Vinagrerilla roja, a plant species adept at making difficult terrains its home.

Vinagrerilla roja (Rumex vesicarius) / the Canary Island bladderdock is one of the most successful endemic plants for colonizing new territory in arid and volcanic areas. The photo was taken on the crater rim of the volcano Montana Bermeja (157 m asl.), located at the northernmost edge of the volcanic island La Graciosa. The island was formed by the Canary hotspot and is today part of the protected Chinijo Archipelago Natural Park which shelters endemic and highly endangered species of the Canary Islands.

The volcano Montana Bermeja is composed of red lapilli (pea to walnut-sized fragments ejected during an eruption) which seems to impede any kind of life. But as the photo shows, the bladderdock is actively growing in this apparently hostile environment. That plant life emerges from such a barren and rough volcanic environment seems almost impossible.

Only very few pioneer species succeed and manage to survive in such harsh environments with little to no soil and under an almost desertic climate. Being located on the northern side of the crater rim enables the bladderdock to capture moisture out of the reoccurring Atlantic winds. As these pioneer species grow, their dead leaves and roots will enrich the soil with organic content providing the base for a chain of ecological succession.

By Katja Laute, researcher at IUEM, Brest, France

If you pre-register for the 2017 General Assembly (Vienna, 22 – 28 April), you can take part in our annual photo competition! From 1 February up until 1 March, every participant pre-registered for the General Assembly can submit up three original photos and one moving image related to the Earth, planetary, and space sciences in competition for free registration to next year’s General Assembly!  These can include fantastic field photos, a stunning shot of your favourite thin section, what you’ve captured out on holiday or under the electron microscope – if it’s geoscientific, it fits the bill. Find out more about how to take part at http://imaggeo.egu.eu/photo-contest/information/.

January GeoRoundup: the best of the Earth sciences from across the web

January Georoundup: the best of the Earth sciences from across the web

The start of the new year sees the launch of a new series here on GeoLog. Drawing inspiration from popular stories on our social media channels, as well as unique and quirky research news, this monthly column aims to bring you the best of the Earth and planetary sciences from around the web.

Major stories

One of the biggest stories of this month was the anticipated release of the average global surface temperatures for 2016. It probably wasn’t a great surprise to discover that newly released National Oceanic and Atmospheric Administration (NOAA), NASA and the UK’s MetOffice data showed 2016 was the hottest year on record. On average, temperatures last year were 0.99℃ higher than the mid-century mean. It marks the third year in a row that Earth has registered record-breaking temperatures and highlights a trend, as climate blogger, Dana Nuccitelli, explains in an article for The Guardian:

“We’re now breaking global temperature records once every three years”

This video, showing NASA global surface temperature record since 1880, illustrates the point clearly. There were no record breaking years between 1945 and 1976, but since 1980 there have been 12.

 

This month also saw the inauguration of the 45th President of the United States. A fierce climate-change denier, Donald Trump’s rise to power has many worried about the future of climate change policy at the White House. To shine a light on the realities of climate change in the face of a largely climate sceptic administration and despite the ever rising global temperatures, The Guardian dedicate 24 hours to reporting on how climate changes is affecting regions across the globe. Among the comprehensive coverage this collection of climate facts stands out.

And it turns out the fears about the newly elected administration may not have been unfounded. Earlier this week the US Department of Agriculture and other federal agencies issued a ban preventing its scientists from communicating with the press and public about their research findings; even on social media. The order has since been rescinded, but US- based scientists remain concerned. In response, the AGU has written a letter to federal agencies in the US defending the protection of scientific integrity and open communications.

Closer to home, central Italy was struck by a sequence of four earthquakes on 18th of January, with the largest registering a magnitude of 5.7. The epicentres were located close to the town of Amatrice – in a region already shaken by several strong, and sometimes devastating, earthquakes in 2016. Later that day, and following a period of very heavy snowfall, a deadly avalanche in the Apennines buried a hotel in the Grand Sasso resort area, which had also been affected by the earthquakes. Although some news reports were quick to suggest the avalanche had been triggered by the earthquakes, researchers will need more data and a more detailed analysis to make this connection.

What you might have missed

While we are on the topic of climate change, a newly published report by the  European Environmental Agency is not to be missed.

“Climate change poses increasingly severe risks for ecosystems, human health and the economy in Europe.”

The document assesses the latest trends and projections on climate change and its impacts across Europe. While the effects of increasing temperatures will be felt across the continent, Southern and south-eastern Europe is projected to be a climate change hotspot with the forecasts showing the region will bear the brunt of the impacts.

A powerful 7.9 magnitude earthquake struck off the coast of Papua New Guinea on 22nd January. While the USGS estimated there was a low risk to property, tsunami warnings were issued across the South Pacific. In the wake of the tremor, the Incorporated Research Institutions for Seismology (IRIS) tweeted this neat ground motion visualisation of the earthquake waves.

A study published in Nature and summarised in Eos, highlights that while overt discrimination of women in the geosciences has not been as prevalent in recent years, many female scientists are still subject to subtle and unconscious bias leading to barriers to success in the geosciences.

Five links we liked

  • NOAA’s new GOES-R satellite for weather monitoring returned its first stunning photos of planet Earth – here are six reasons why the data it will acquire matter.
  • Snow fell in the Sahara for the first time in 37 years! This photogallery shows the usually red sand dunes of the desert covered in a sprinkling of white snow.
  • Scientist at The University of Cambridge have published the first global map of flow within the Earth’s mantle, showing that the surface moves up & down “like a yo-yo”.

The EGU story

At the EGU, the highlight of the month is the number of abstracts we received from researchers wishing to present and discuss their science at the EGU 2017 General Assembly. With over 17,500 abstracts, and an improved set-up to accommodate the high number of expected participants, the conference promises to be the largest and most exciting to date. We look forward to welcoming everyone in Vienna on 23–28 April!

And don’t forget! To stay abreast of all the EGU’s events and activities, from highlighting papers published in our open access journals to providing news relating to EGU’s scientific divisions and meetings, including the General Assembly, subscribe to receive our monthly newsletter.

EGU Photo Contest 2017

EGU Photo Contest 2017

If you are pre-registered for the 2017 General Assembly (Vienna, 23 – 28 April), you can take part in our annual photo competition! Winners receive a free registration to next year’s General Assembly!

The eighth annual EGU photo competition opens on 1 February. Up until 1 March, every participant pre-registered for the General Assembly can submit up three original photos and one moving image on any broad theme related to the Earth, planetary, and space sciences.

Shortlisted photos will be exhibited at the conference, together with the winning moving image, which will be selected by a panel of judges. General Assembly participants can vote for their favourite photos and the winning images will be announced on the last day of the meeting.

If you submit your images to the photo competition, they will also be included in the EGU’s open access photo database, Imaggeo. You retain full rights of use for any photos submitted to the database as they are licensed and distributed by EGU under a Creative Commons license.

You will need to register on Imaggeo so that the organisers can appropriately process your photos. For more information, please check the EGU Photo Contest page on Imaggeo.

Previous winning photographs can be seen on the 20102011, 2012,  2013, 2014, 2015 and 2016 winners’ pages.

In the meantime, get shooting!

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