Towards the future: A summary

This starting this blog back in October 2015, it has taken me on a journey. A journey through time, a journey to various corners of the world, and a journey into the colourful lives of various societies and civilisations which have inhabited this world at one point or another.

We have discussed the role played by climate change in the collapse of past civilisations including the Norse colony in Iceland (Norse colony and the climate change catastrophe), the Saharan tribes (Green Sahara), the Mayan civilisation of South America (Climate and the classic Mayan collapse), and the inhabitant of Rapa Nui or Easter Island, Pacific Ocean (Lessons from Rapa Nui).

We have explored the possibility of that humans have delayed the onset of a glaciation which would have occurred without the effect of the enhanced anthropogenic forcing on the climate system during the onset of the agricultural revolution (Rivalling the forces of nature).

We have provided an insight into the issues facing societies today as they battle against climate change including an African farmer battling against extreme precipitation events (At the front line against climate change), Greenland communities threatened by retreating sea ice (Melting away and When the sea took the land), extensive droughts in the region of the Sahel (Do they know its Christmas?), and widespread flooding which hit the UK over the Christmas period (When the floods ruined Christmas).

Future projections by climate models and the effects of societies were explore, including the blog which explored how the Middle East could become inhospitable for human life by the year 2100 (Middle East Meltdown) and the blog which explored how the Sahara is project to become increasingly vegetated (A greener future). Solutions which could provide fundamental for societies to adapt to climate change were also explored including how to reverse desertification (Reversing desertification).

Of course, we could not ignore the climate discussion in Paris which dominated the news for a couple for weeks, and we explored how much interest did the general public in the UK have in the COP21 discussions (Alleyes on Paris?).

A blog which takes a more general take by discussing if we are today causing our own destruction (Are we committing and ecocide?) summarizes our findings and highlights the  extreme complexity of the relationship between humans and the climate. Despite the success of COP21 in Paris, enhanced anthropogenic forcing are still predicted to continue increasing at an alarming rate for the next century. Understanding how changes to the climate system will impact societies today is fundamental for our species’ survival.

So I'm going to leave you with this video below - a video which manages to summarize without the need for any fancy, motivational words, exactly why Gaia is worth fighting for. 

Over and out. 

Erin  

Lessons from Rapa Nui

Figure 1. The famous statues of Easter Islands (source)

Rapa Nui (Easter Island) is a one of the most remote islands in the world.  It is a small volcanic island of 164 km², low relief, and low rainfall. It is another classic example of a complex societal collapse which is proving to be one of the most important examples with regards to holding lessons for the future. As reported by Hunt (2007), when and how the first humans discovered Rapa Nui is still highly debated. Today, cultural evidence continue to dominate the landscape as huge sculptures were erected throughout the island between AD 1200 and AD 1650. At peak, the population may have reached 10,000, yet in AD 1650, this dramatically reduced as the civilization headed for collapse. Important lessons could be learnt from this societal collapse story with regards to the future therefore this blog will explore the main drivers behind the collapse with special reference to the role of climate change. 

A classic view of the Easter Island collapse story is one of 'ecocide' as the human population drove its own destruction by exploiting its natural resources, degrading the island's lands, causing extensive deforestation, and driving the extinction of plants and animals (Diamond, 2005). Extensive deforestation has received considerable attention, as this would have prevented the society from building boats and rafts to escape from ecosystem damage. Diamond writes that ‘‘in just a few centuries, the people of Easter Island wiped out their forest, drove their plants and animals to extinction, and saw their complex society spiral into chaos and cannibalism.’’. 

This has been heavily criticised as presenting an environmental deterministic view. There exists no reliable evidence of a large population which could not sustain itself followed by an abrupt,  cataclysmic collapse (Hunt., 2007) and Rapa Nui does not appear to represent a case of ‘‘ecocide.’’. Instead, the arrival of Europeans to the island, bringing with the new species, diseases and slave-trading has been suggested to play a more crucial role (Peiser, 2005). It has been reported that the societal collapse on Easter Island is ‘‘one of the most hideous atrocities committed by white men in the South Seas" (Metraux,1957). 

Other theories suggest that the arrival of the European bought rapidly reproducing rats to the islands, and that this invasive caused considerable damage to plants and animals, dramatically changing the islands food chain and resources and driving the society towards collapse (Hunt, 2007). This theory has been heavily critisiced on the basis that the rats could not have reproduced fast enough to cause such devastating consequences (Mann et al., 2008). 

Figure 2: An identified period of intense deforestation which coincides with an El Nino-Southern Oscillation period (source)

A studies which used pollen to reconstruct vegetation chance across the island found a correlation between a period of major deforestation and an intense El Nino-Southern Oscillation period (figure 2, Cobb et al. 2003). ENSO events result in a change in sea surface temperature, which leads to the lowering of biomass production and upwhelling of nutrients. This would have reduced the availability of marine resources around the island, a key source of protein for the islanders. An abrupt ENSO event could have caused a significant decline in food resources, driving an expansion in agriculture, and reducing the availability of wood to make boats would have also made fishing ground inaccessible. The role of climate change has a more recently been confirmed by a more recent study which identified period of drought being experienced on the island prior to the collapse of the civilization at AD1180-1290 (Mann et al. 2008). Stratigraphic records from lake sediment cores looking at sediment, charcoal and pollen stratigraphy suggests that the lake dried out during this period of drought identified by a hiatus in sedimentation. The study concludes that it looks likely that latitudinal shifts of tropical storm tracks, changed to the moisture balance across the island triggered the period of drought.

As we have previously explore in many past blogs, the relationship between civilisations and the climate is highly complex! Both interlink with each other. Hence, when attempting to understand what caused past civilisations to collapse, it is difficult to isolate individual signals from the records and pin pointing a specific climatic change or societal driver. However, many key lessons can be learnt from past societies including the need to be aware of the damage that we are causing to the planet, the need to plan and prepare with adequate mitigation measures, and the need to be flexible and adaptable to change. Only then can we survive this world's dynamic climate. 
 

Rivalling the forces of nature

Figure 1. Future Earth? (source)

Global average temperatures throughout the Holocene were relatively stable in comparison to previous warm or interglacial period in the Earth's history. It was originally thought that this was the result of natural climatic drivers and that humans did not influence the climate until two centuries ago during the Industrial Revolution which saw a rapid surge of greenhouse gases into the atmosphere (figure 2). This has been challenged by a hypothesis which states that without the anthropogenic factor, the Holocene should have experienced gradual cooling under a natural state, and that anthropogenic emissions first started altering the climate 8,000 years earlier (figure 2, Ruddiman, 2003). This blogs explores the overdue glaciation hypothesis.  

Figure 2: Changes in atmospheric greenhouse gases and global average temperature over the last 8,000 years (source)

Ruddiman (2003) bases his hypothesis on two key point. Firstly, atmospheric gases stopped following the natural oscillating trend driven by Milankovitch cycles seen throughout most of the Quaternary and instead of falling, CO₂ levels began rising 8,000 years ago and CH₄ around 5,000 years ago. Secondly, numerous archaeological, historical and geological evidence exists which points towards a large social shift in Eurasia 8,000 years ago as the Neolithic Revolution drove hunter-gatherers into settled farmers. This gave rise to the domestication of plants and animals, change in landuse and an increase in population. Bringing both together, evidence shows how the rise of agriculture and extensive deforestation around 8,000 ago coincides with the gradual rise in CO₂ whilst the expanding of rice irrigation occurred around 5,000 years ago coinciding with a rise in CH₄. Together, these changes have contributed to the 0.8°C rise observed above the Holocene baseline which has been enough to stop the natural cooling trend and prevent the Earth entering a glacial period. 

The climate model GENESIS was created to test the hypothesis to see how the Earth would have responded if the greenhouse gases had not increased since the agricultural revolution (figure 3) (Ruddiman, 2005). The model showed how temperatures today would be 2°C colder and the Earth would be one third on the way to maximum glacial conditions. Other studies also support the findings showing how changes in orbital configuration and solar radiation based on oxygen isotope suggest that global ice volumes should have reached minimum 6,000 years ago (Berger and Loutre, 2003). 

Figure 3. An artists impression of the Agriculture Revolution (source)

The overdue glaciation hypothesis has received three main criticism all of which are address by Ruddiman (2007). Firstly, many have criticised Ruddiman's use of the previous three interglacials to compare against the Holocene (MIS1) since the orbital configuration of marine isotope stage 5, 7 and 9 are significantly different to the Holocene. During MIS 5, 7 and 9, eccentricity was higher than for MIS 1 resulting in more extreme solar radiation received on Earth. MIS11 has been proposed as a better analogue for MIS1 due to low eccentricity. The duration of MIS11 was significantly greater than other interglacials with marine sediments used to reveal how it lasted for 28,000 years, and this would therefore suggest that MIS1 has 16,000 years until the current interglacial come to termination (McManuset al., 2003). Ruddiman fires back with an argument that aligning the orbital configurations is flawed and that cooling had began during MIS11 at the isolation level comparable to that of MIS1 (Ruddiman, 2005). 

Secondly, many have question if humans have the capacity to increase greenhouse gases to reach such levels. To account of the 230 ppb anomaly found for methane, studies have suggested the expansion of wetlands across Eurasia but this has been rejected due to differences in the concentration between Greenland and Antarctica (Chappellaz et al. 1997). Ruddiman argues that substantial evidence from sedimentary records from deltas in the tropics show increased sedimentation and provide evidence of extensive deforestation  and widespread erosion (Roberts, 1998). Thirdly, detailed reconstruction of the Holocene temperature reveal small fluctuations around 10ppm in CO₂ in the last 1,000 years whilst human activity continues to increase. Ruddiman provides a possible explanation for this by claiming that three key major pandemics occurred over the last 1,000 years during the Roman Era (Cartwright, 1991), the Black Death pandemic during the Dark Ages, and the arrival of the Europeans in American 1942 (Denevan, 1992). 

Ruddiman provides a strong argument in favour of his overdue glaciation hypothesis. The implication of this provides important for defining the start of the Anthropocene which marks a moment in the Earth's history then humans activity becomes so profound that it rival the geological forces of the Earth and changes the course of the Earth away from its natural variation (Crutzen and Stoermer, 2000). Ruddiman's work shows how the Holocene was not free of human influence as previously believe and this has significant implications with respect to the current impact anthropogenic forcing are having on the current climate and on future climate. 

When the floods ruined Christmas

Figure 1: A rescue scene from the streets of Carlisle (source)

Over the Christmas period, large parts of the British Isles were battered by the latest 1/100 year storm event, Storm Frank, which caused widespread flooding and extensive damages across the UK. Britain saw high winds, flood defenses being breached, thousands evacuated from their homes and record breaking water levels. A large section of a bridge in the town of Todcaster collapsed under the force of the River Ouse, isolating a section of the community for hours which caused social stress and instability (see video below). Cumbria was hit badly as over 3,500 homes were evacuated according to the Observer, and Capel Currig saw 201.6mm of rain fall over 48 hour period between Christmas Day and Boxing Day. This all comes following the mildest December in the UK since records began in 1910 as an average of 9.5°C was observed for December according to the MetOffice. This was 4.8°C warmer than the average and 2.8*C higher than the second highest average set in 1938.

Can we blame global warming? Based on the fundamental laws of thermodynamics and the Clausius-Clapeyron equation, which states that warmer air can hold more water, climate models predict that in the future warmer world, dry areas will become drier and wet areas will become wetter. A recent study published in Science compared ocean surface salinity between 1950 and 2000 to establish a relationship between ocean salinity, rainfall and evaporation and used this to build hydrological climate models. Durack et al. (2012) found that over the designated 50 year period, the global cycle of rainfall and evaporation has accelerated by four per cent due to the enhancement in rainfall and evaporation. The study warns how future changes will not be uniform, and that 'changes to the global cycle and the corresponding redistribution of rainfall will affect food availability, stability, access and utilisation.'. 

It is possible that Britain is beginning to experience the direct impacts of climate change. As global warming increases in the future, the hydrological cycle is predicted to continue to increase, bringing more rain to already wet areas, and less rain to already dry areas. It is crucial that the Government invests in planning and preparation of flood defenses and coping strategies in an attempt to reduce future impacts of storm events and social instability. 

Middle East Meltdown

(source)

Under a 'business-as-usual' scenario, a recent study suggests that the region around the Arabian Gulf in the Middle East could become inhospitable for human life by the year 2100. To define a threshold to mark the climatic conditions tolerable by a fit human, Pal and Eltahir (2015) used a 'wet-bulb temperature' measure. This is a combination of temperature and humidity which is used to define the survivability of humans under certain climatic conditions. It is believed that the fittest human could last for up to six hours in a wet-bulb temperature of 35°C. The recent study published in Nature used an ensemble of high-resolution climate models to project future wet-bulb temperatures and found a specific regional hotpot in the region of the Middle East (figure 1). In July 2015, temperatures reached 34.6°C in Bandar-e Mahshahr, Iran for around an hour, extremely close to the 35°C wet-bulb temperature threshold identified as being fit for human survival. As the global surface temperatures continue to increase into the future, high evaporation rates from the Persian Gulf will increase humidity across the region. Furthermore, it is a region of low elevation and clear skies, conditions which makes the Middle East a hotspot for extreme conditions. Under the 'business-as-usual' IPCC scenario, this study suggests that the Middle East could see the 35°C threshold exceeded by 2100, making the region inhospitable for human life and driving major migration of people from the region. 

This is a region with an ancient history which supports some of the world's earliest civilizations in Mesopotamia and the Fertile Crescent. It is the birthplace of many religions including Christianity, Islam and Judaism and a diversity of cultures and societies. Today, the region supports many of the world's major cities including Cairo (Egypt), Istanbul (Turkey), and Baghdad (Iraq). This study shows how the impacts of future climate change could have disastrous consequence for the societies inhabiting the region by 2100 by increasing threat to water and food security, driving a substantial rise in climate refugees from this region and a significant change to the world's demography. 

Figure 1: Spatial distribution of extreme wet-bulb temperatures (a, b, c) and extreme temperature (d, e, f)  for each historical GHG concentrations (a, d) and for representative concentration  pathway RCP4.5 (b, e) and RCP8.5 (c, f) (source). 

Climate change six years on

Figure 1: Maria Mallik, Bangladesh (source)

Back in December 2009, the Observer published an article describing the lives of the families of four new-born babies from different corners of the world and their struggle to cope with the impacts of climate change. They recently returned to meet those children to see how their lives have changed in the last 6 years. This is the generation which will feel the greatest impact of the actions of today’s society.

The father of Maria Mallik has been a rickshaw puller in Bangladesh for 30 years, but today the rising temperatures and increasing pollution is making him weak. On top of this, the family of seven live on the coastal outskirts of the city in Barguna district, an area which has seen a significant rise in sea levels due to global warming over the last few decades. When the sea floods onto agricultural lands, this increases the salinity concentration and destroyed the productivity  of the lands, pollutes the drinking water and destroys homes. The last decades have seen an increase in intensity and frequency of cyclone and storm surges which case widespread damage to these coastal regions. Coastal erosion is driving more and more people to migrate away from these areas. Maria’s father explains how the community are well aware of climate change and the effects are felt on a daily basis -  “everyone in our community now knows that climate change is now a big threat. Everyone is tired of speaking about it. We are poor so there is no way out.”.

Figure 2: Denislania da Silva, Venezuela (source)

Denislania da Silva is a six-year old member of the indigenous Macuxi people who’s homeland is around Barro, Venezuela (figure 2). In 2009, their lands were threatened by multinational companies who wanted to turn their marshlands and key hunting grounds into rice plantations to feed the growing world population. A few years ago, the Brazil supreme court has rule in favour of the Macuxi, and that the lands should stay in their hands.  But today, the Macuxi face a different threat. The effects of climate change has been felt in this region as the climate is becoming drier, temperatures have increased, and an increase in threats to water security. Seasons have become less distinct, weaker rainy seasons and warmer dry season causing water reservoirs to dry up. Denislania’s mother recalls - “Our river used to be abundant but it’s suddenly dried up. The fish that we used to catch have disappeared. Even when there is only rotten old fish, people will buy it. Our wildlife is also leaving – all because of the drought. I sometimes wonder if God is making us die from drought.”

Figure 3: Olomania Mutonka, Kenya (source)

Back in 2009, the family of 6-year old Olomania Mutonka were fearful of the future as droughts were threatening their very survival in the outbacks of Kenya (figure 3). No rain has fallen for a year, cattle are dying, and food and water security is reaching levels of extreme desperation. An increase in the intensity and frequency of drought events has been observed in this part of Kenya over the last few decades as was explored in a past blog, and by 2020, 75 million people are predicted to suffer from water stress in east Africa. Today, Olomania’s mother travels for six hours to collect water, a journey which she must walk every other day, and this water is from an old, abandoned quarry that contained toxic, salty water. She says - “If the drought continues all our animals will die and we will be left with nothing. We will have no money to pay our children’s school fees. The Olkejuado river dried up a long time ago and so we have nowhere else to fetch water from. That is what we have to drink.”

Figure 4: Fretelina de Oliveria, Timor-Leste (source)

Fretelina de Oliveira lives in Au-Hun on the island of Timor-Leste (figure 4). “Six years ago the climate was better, normal and not as hot as it is now” says Fretelina’s father. Over the last few decades, the island has been hit by numerous drought events and an increase in temperatures, significantly decreasing the productivity of the islands main agricultural product, maize. During the dry season the hot climate has made life ‘life unbearable’. But during the rainy season, a dramatic change is seen as the village is devastated by floods and heavy rains. The seasons are ‘erratic’, and as temperatures continue to increase in the future, the intensity of the hydrological cycle will also continue to increase.

 These are the stories about four children are the struggle of them and their families as they battle against the ever increasing effect of climate change. Societies today are feeling the effect. Let hope that in the near future that these stories will not develop into stories of societal collapse.

Climate and the classic Mayan collapse

Figure 1. A Mayan temple (source)

Every year, thousands of tourists flood to Central America to visit the ruins of the ancient Mayan civilisation. The pyramids, temples and monuments, which are today entangled in thick jungle vegetation, are only a glimpse of a once fruitful, sophisticated civilisation which possessed the knowledge of astronomy and mathematics, and crafted beautiful jewelry out of obsidian and jade. At the peak of their success, the Maya population in the Yucatan Peninsular, reached 13 million around 750 A.D. By 950 A.D, the population had significantly declined and their city, falling into ruin, was left in the hands of the jungle once again. To this day, this 'terminal Classic collapse' story remains a great mystery as to what drove the collapse of this successful, ancient civilization and this blog aims to explore the role of climate change in driving this collapse.

Haug et al. (2003) claims that the key behind this collapse story, lies in the geographical location of the Yucatan Peninsular. The Mayan lands fall between 17-22*N and is a seasonal desert receiving 90% of its rainfall between June and September, with a pronounced dry season throughout the rest of the year. Its rainfall patterns is driven mainly by the movement of the Intertropical Convergence Zone (ITCZ) which moves northwards in the summer bringing rain over Central America, and vice versa in the Winter months. As a result, the Maya built massive, sophisticated drainage systems throughout the cities, reservoirs on hilltops which used gravity to distribute the water, and complex irrigation systems.  They were highly dependent on the movement of the ITCZ to replenish their freshwater supplies; a failure of this climatic phenomena could potentially have been catastrophic.

Haug et al. (2003) and later Peterson and Haug (2005) measured the concentration of titanium and iron elements from lake sediments and used them as a proxy for river discharge and changes in the hydrological cycle. They noted a long period of extended drought across Central America with multiple punctuation of intense drought periods centered around 810 A.D, 860 A.D, and 910 A.D, coinciding with the collapse of the Maya (figure 2). Peterson and Haug state that the significance of this discovery show how tightly couples the collapse of the Maya was to environmental constraints.

Figure 2. The titanium concentrations from the lake sediments identifying the terminal Classic collapse as a possible driver of the Mayan collapse (source)

Diamond (2005), described the collapse as an 'ecocide' and suggests that the society destroyed the environment which the depended upon and essentially causing their own collapse. Environmental degradation is being highly blamed by Diamond as the Maya damaged their lands through intense agricultural practices including terracing, irrigation, deforestation and draining field. Over-reliance on a maize monoculture, a humid-climate which prevented the long-term storage of food, a lack of domesticated animals to aid with agriculture and a protein-poor diet, were also contributing factors, as was the lack of friendly neighbours and the highly structured, unequal, social hierarchy (Diamond, 2005).

This view by Diamond has been highly criticised, as many authors claim this view to be an environmental deterministic view. This is a concept which suggests that the physical environment sets a constraint on societal development, a concept which as Coombes and Barber (2005) show, has received much criticisms. It is seen as shifting the blame and responsibility behind collapse stories away from humans and onto a factor beyond our control. Furthermore, they claim that palaeoenvironmentalists are too ready to blame the collapse of a civilisation on climatic change solely based on an apparent correlation in the proxy record.

Hodell (2011) further this by stating an argument by highlighting the weaknesses of palaeoenvironemntal studies. The poor resolution and the inaccuracy in dating records are among the few factors contributing to the uncertainty and ambiguity in palaeoenvironmental records. As Aimers (2011) states, palaeoclimate data must be interpreted with care and the evidence is not robust enough yet to blame the collapse of the Mayan civilisation on climate change alone. A greater collaboration between climate scientists and archaeologists is needed (Aimers, 2011).

Collapse may not be the correct term to describe the decline in population or the abandonment of the Maya cities, as an increase in population was seen in other regions in Central America which suggests that some of the Mayan migrated away from these marginal areas to rehabilitate elsewhere (McAnany, 2010). It is clear that we cannot blame one single factor on the collapse of the Maya civilisation but that it was possibly due to multiple, cascading factors - an unstable society pushed by climate chang across their threshold and beyond stability. Although a dramatic depopulation did occur in some regions, seven million decendants of the once great Maya civilisation continue to live in remote villages across Central America. It was certainty not a complete obliteration (Gause, 2014).

When the sea took the land

A previous blog titled 'Melting Away' has been written on how the temperatures in the Arctic are increasing at a rate higher than the global average and on the consequence of climate change on societies today living in the Arctic circle. As a more recent development, on December the 15th, the National Oceanic and Atmospheric Administration (NOAA) issued a press statement stating that "the Arctic is warming twice as fast as other parts of the world". Extensive melting was mostly observed in parts of west Greenland, northwest Alaska, and Baffin Bay, and a 5°C increase in temperatures above the average was measured in some areas during 2015 (figure 1). The report presented statistical description of the observation for the Arctic region for the year 2015 and amongst the key findings were:

• average Arctic temperatures  were seen to be 2°C warmer than the global average
• minimum sea ice extent for September was 29% less than the average
• maximum sea ice extent occurred 15 days earlier than the average
• maximum sea ice was 7% less than the average
• snow cover has decline 18% per decade since 1979
• a substantial increase in green vegetation already seen to respond to the warmer climate
• a noted change the habitat of walruses and subarctic fish




Figure 1: A map and a graph demonstrating how the temperatures across the Arctic are increasing above the average rate (source)

A documentary which might be of interest to some of you follows the story of an Arctic village, Kivalina, northern Alaska, as erosion of the land by the force of the sea is threatening their village. The documentary shows how in the past thick sea ice protected the village from the impacts of sea waves. Today, the rising temperatures have melted the sea ice and the soft land is crumbling into the water and the waves hit the shores. A short trailer can be view below, and the documentary itself is airing this Sunday at 9pm on Al Jazeera.

Reversing desertification

Figure 1. Desertification in Oman (source)

Desertification is land which is turning into desert and approximately two thirds of the land on Earth is desertifying (figure 1). It has destroyed many societies in the past, and is causing great problems to societies around the world today. It occur when soil organic matter is stripped away to reveal bare, hard ground which leads to increased runoff and evaporation. Furthermore, the decomposition of the soil organic matter releases carbon to the atmosphere which is changing the microclimate in the short-term and the macroclimate in the long-term. 

Societies around the world have been taught over recent decades that desertification is caused by overgrazing by livestock and as a result, large groups of livestock has been discouraged. In the 1950's Allan Savory, Zimbabwe's land degradation expert, suggested that in order to reduce and reverse the widespread problem of desertification in their national parks, the number of elephants in the park must be reduced. This led to a massacre of 40,000 elephant in order to bring their levels down to a level the land could sustain. Today, Savory admits that 'it was a terrible decision' as the problem of desertification over the following years got worse, not better. In Savory's words - ‘We were once as certain that the world was flat! We were wrong then and we are wrong again!’.

In a recent Ted Talk video, Savory presents evidence challenging the idea that livestock cause desertification. Due to evolutionary pressures from predators, grazing animals have developed to form large packs of herds. These herds are continually on the move, looking for new vegetated lands, and it is this movement that prevents overgrazing. Savory proposes, that there is only one option left to recent desertification - "to use livestock, bunched and moving, as a proxy for former herds and mimic nature. There is no alternative left for mankind.". 

Societies are now encouraged to use holistic management and planned grazing process to reduce desertification. Today, there are people who are teaching farmers in societies across the world how to plan and manage their herds. They are being encouraged to keep their animals in pens overnight to prepare crop fields and significant increase in crop yield has been seen. To compare, we see lands in Zimbabwe previously subject to desertification (figure 3) which have seen dramatic change since the introduction of the holistic management and planned grazing process and increasing the number of herb grazing animals by 400% (figure 3). Furthermore, increasing the vegetation will allow carbon from the atmosphere to be stored in grassland soils and vegetation and in the long-term this could help prevent global warming. 



Figure 3. Lands in Zimbabwe in before and after planned holistic management was used. 

Today, we see societies turning to using this low-cost method of planned holistic management since it is the last hope that they have of saving their families and saving their cultures. Desertification is causing hunger, poverty, social unrest and wars and is playing a significant part in global climate change.  Planned holistic management and moving herds of livestocks mimicking nature is suggested by Alan Savory as a critical technique to reverse desertification. 

A greener future

Figure 1: A young Sahelian farmer tends his garden (source)

The brave 2 million inhabitants of the Sahel region in Africa have faced sever prolonged droughts in recent decades as was explored in the last blog. Since the 1960-1980's drought-period, societies have attempted to reclaim their land by stabilizing sand dunes, cultivating trees, building rock walls to stop erosion, and sowing seeds in pits which have been dug to catch rain (figure 1, 2). Advancing on this, new studies are emerging which suggest that global warming could bring a glimmer of hope of a wetter, more tolerable climate. Issues regarding desertification, water and food security could be made history claimed the Guardian, as future climate change could stop the drying of the Sahara. Already, scientists are reporting an increase in rainfall and the regreening of the Sahara. 

Figure 2: Sahelians fence sand dunes to prevent erosion (source)

 Haarsman et al., (2015) created a climate model of the Sahel region and simulated the effects of global warming under different representative concentration pathways (RCP) between 1980 and 2080. A significant increase in rainfall within a couple of decades was found and the study reports that the increase could strongly reduce the probability of future prolonged droughts. The mechanism behind the changing climate in the Sahel region is analogues to the polar amplification in the Arctic which is causing significant increase in temperatures above the average global rate. Cook and Vizy (2015) reports a substantial increase in Sahara surface temperatures at a rate of 2-4 times greater than the average tropical increase over the last 34 year period. Global warming will increase land temperatures sooner than ocean temperatures. While the warming across most of the globe involves the full depth of the atmosphere, the warming in the Sahel region is concentrated at the surface since the dryness of the desert is limiting the longwave radiation, changing the air pressure and the weather.

Already, in the southern Sahel, the band of rainfall has moved northwards at a rate of 9 km per year since 1982. Dong and Sutton (2015) present observed data of a 0.3 mm increase per day in rainfall since 1996 against the average for the 1964-93 period. They suggest that the recovery of the Sahel rainfalls to the levels pre 1960-1980 drought-period is a response to anthropogenic greenhouse-gas and aerosol forcing, and they predict that the recovery is likely to be sustained or amplified in the near-term. Satellite images from AVHRR (Advanced Very High Resolution Radiometer) sensors demonstrate how the vegetation cover in the Sahel is responding to the change in rainfall by expanding northwards by 3 km per year (figure 3). Animals which have not been seen in some regions over the last few decades are returning such as gazelles and ostriches to some areas of Morocco.

Figure 3: The same area in 1975 (left) and 2005 (right) in southern Niger (source)

National Geographic (2010) interviewed Stefan Kropelin, a climate scientists who has been studying the climate of the Sahara region for decades and he stated how in recent years shrubs are expanding and different species of vegetation are appearing (figure 4). Kropelin states "the nomads there told me there was never as much rainfall as in the past few years. They have never seen so much grazing land. Before, there was not a single scorpion, not a single blade of grass. Now you have people grazing their camels in areas which may not have been used for hundreds or even thousands of years. You see birds, ostriches, gazelles coming back, even sorts of amphibians coming back.”.

Figure 4: Sahelian women tending their shrubs (source)

Desertification, drought, famine and conflict are the usual stories that are entangled with future global warming. Yet, the accumulating scientific evidence and the stories which are coming directly from the people living at the forefront of climate change in the Sahel are indicating a different scenario, a blossoming, regreening Sahara and possibly a more fruitful future for the societies of the Sahel.