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Around half of Earth’s terrestrial land surface remains relatively untouched by humans, a new study has found. Using a combination of recent global maps of human influence, researchers were able to calculate the average influence humans are having on ecosystems worldwide. These findings provide some hope for our ability to protect and conserve the regions of the world which, at this moment in time, remain relatively ‘wild’.

For as long as humans have existed they have impacted their surrounding environment. This era of human dominance has been coined the ‘Anthropocene Era’ by some scientists, who argue that Earth is being overwhelmingly defined by the actions of humans above natural processes. As the devastating effects of anthropogenic climate change unravel worldwide, it is hardly surprising that many people favour this view. 

Whilst it is evident that mankind profoundly impacts the natural environment, being able to quantify this is more challenging. Initial efforts to establish the global extent to which human civilisation has impacted Earth began in the 1980’s when ‘wild’ areas were identified and mapped, with efforts progressing through the following decades. 

In the study, researchers combined four different global maps of human influence to determine the average human influence for different regions in the world. Interestingly, their findings show that whilst the maps analysed use different methodologies they show similar results for the level of human influence across the globe.

They conclude that just over 50% of Earth’s land surface can be classified as having low human influence or being untouched completely, with a range of 48-56% depending on the type of human influence map used. 

Importantly, the level of human influence varies significantly from biome to biome. Cold landscapes such as boreal forests and tundra have experienced ‘very low’ to ‘low’ human influence. By comparison, temperate grasslands, tropical coniferous forests and tropical dry forests have experienced much greater levels of human influence with less than 1% of these regions being classified as having ‘very low’ human influence. For these ecosystems, it is a grim illustration that human civilisation has completely altered the natural environment.  

Ecosystems which still remain relatively untouched by humans provide a number of beneficial services to mankind such as supplying clean water and providing natural flood control as well as being able to protect against some of the impacts of climate change. One example of this is urban wetlands, which are being constructed in order to adapt to extreme weather events and flooding in urban areas, such as in Laos, by controlling water flow and filtration. These ecosystem services are also therefore crucial for improving overall human wellbeing. 

For ecosystems which have seen significant levels of human influence, all hope is not lost. Certain agricultural practices such as ‘carbon-smart’ farming, which helps to restore organic matter in the soil and increase soil-biodiversity, can actually help to promote biodiversity rather than threaten it, whilst pollinators can thrive in urban areas. Therefore, these human-dominated landscapes can actually help mitigate the climate crisis and support biodiversity if managed effectively. 

Protecting the world’s unscathed lands is beneficial for a number of reasons, the authors of the study note, as they are able to “help purify air and water, recycle nutrients, enhance soil fertility and retention, pollinate plants and break down waste products.”

Lead author of the study, Jason Riggio, who is also a postdoctoral scholar at the University of California, provides an encouraging perspective on leaving landscapes untouched, highlighting that “if we act quickly and decisively, there is a slim window in which we can still conserve roughly half of the Earth’s land surface in a relatively intact state.” 

A key aim of the study was to provide insights for the 15th Conference of the Parties to the Convention on Biological Diversity (CBD), to be able to set specific and more ambitious targets to conserve the world’s ecosystems. The meeting was due to take place in China later this year, but has been pushed back as a result of the COVID-19 pandemic and is now set to take place between the 17-30th May next year. 

Currently 20% of Earth’s terrestrial land surface is either classified as built up urban areas or cropland and with the global population expanding, this proportion will undoubtedly increase. Going forward, it is critical that we protect these ecosystems which remain relatively intact by ensuring conservation efforts are targeted and relevant. In the lead up to the CBD next year, ambitious targets are gaining momentum and the hope is that by 2050, at least half of the Earth’s surface will be conserved. 

Human civilisations can still populate a landscape and have low influence over its environment but it is a case of taking a more balanced approach towards conservation efforts. The focus needs to be on ensuring that resource needs, along with the protection of ecosystem services and biodiversity, are secured. Professor Riggio raises the point that “achieving this balance will be necessary if we hope to meet ambitious conservation targets” but highlights that “our study optimistically shows that these targets are still within reach.”

As cities are forced to adapt to the challenges of the climate crisis, communities are moving away from traditional engineered responses to using ecosystem-based adaptation services.

Communities worldwide have become more vulnerable to extreme weather conditions and natural disasters caused by climate change. The Global Climate Risk Index 2020 reported that globally, 495 000 people have died as a direct result of more than 12 000 extreme weather events. The index also reported that the world economy has lost US$ 3.54 trillion (in purchasing power parities) from 1999-2018 due to extreme weather conditions. In the past, engineered solutions have been implemented to mitigate the effects of the climate crisis. However, local communities are now adapting through natural solutions called ecosystem-based adaptation (EbA). 

Ecosystem-based adaptation services involve using natural services provided by the local ecosystem to help minimise the impacts of climate change on local inhabitants and biodiversity. The approach aims to provide long-term ecological and socio-economic benefits to local residents. A briefing released by the UN Environment Programme (UNEP) shows that EbAs are economically viable solutions as they can be more cost-beneficial than engineered solutions. Currently, EbAs are being implemented in a range of ecosystems, including mountains, coasts, wetlands, drylands and urban cities.

Examples of Ecosystem-Based Services:

Madagascar’s Blue Forest

For decades, mangrove forests in Madagascar have undergone high rates of deforestation for urban development, agricultural purposes and wood use. Globally, mangroves are declining at a rate of 1-2% annually, however, in comparison to previous decades, the rate of mangrove loss is in decline. This could suggest growth in awareness among communities of the importance of mangroves. Mangroves are sinks which are able to sequester more carbon than other kinds of forest systems and at times up to 3-5% more carbon than upland tropical forests. Studies suggest that mangroves also have the ability to adapt to three millimetres of rising sea levels annually. Because of their resilience, mangroves are now being used as a tool in the fight against the climate crisis.

Madagascar has restored 1 200 hectares of mangroves to adapt to rising sea levels and to facilitate large amounts of carbon sequestration. The country implemented a combination of engineered and ecosystem-based approaches. To combat rising sea levels, along with the restoration of the mangrove forest, a 1 km sea wall has been built as a defence in the cities of Manakara and Toamasina to reduce coastal erosion. The initiative of combining approaches has resulted in a more resilient coast line.

The Cloud Forest of Xalapa

Xalapa, a city situated in the foothills of Mexico, has also embraced EbA, in partnership with the UNEP. The city is surrounded by a cloud forest, an indigenous rainforest located in the mountainous regions. The forest plays a major role in carbon sequestration and in providing water to the inhabitants of Xalapa, controlling the water flow. Trees also reduce the frequency of landslides and erosion through soil retention, which in turn prevents flooding and droughts.

Due to deforestation, the forest has been reduced to one percent of its original size. Locals are threatened by the climate crisis as changing temperatures and irregular rainfall has caused landslides in the urban settlements nearby. Reports suggest that by 2039, the forest could experience a temperature rise of 1.8 which will be detrimental to the ecosystem, as well as to local farmers. To minimise the damage caused by these landslides, the city is working to restore the cloud forest and use the trees as an ecosystem-based adaptation tool for. Restoration efforts include planting montane forest species on the mountain slopes, planting native riparian plants along streams to conserve the soil, and building ditches and berms for soil retention and improved water infiltration.

Urban Wetlands of Laos

Laos has been frequently impacted by urban flooding as a result of the climate crisis, which has been detrimental for the economy; the total damages and losses caused by flooding in 2018 cost the economy an estimated US$371 million, exacerbating poverty and placing further pressure on resources. Laos clearly needs a long-term solution should flooding become the norm for the country (as it appears to be becoming) and in mid-November, the UNEP announced a project in the cities of Vientiane, Paksan, Savannakhet and Pakse, that will help 10% of the country’s population become resilient to climate change.

The project takes an alternative route from the traditional urban management approach implemented through infrastructure. Instead, the goal is to restore 1 500 hectares of urban wetland and stream ecosystems; these ecosystems play a major role in regulating water flow and filtration and restoring them will reduce the flooding that has been plaguing the country. The Deputy Director-General of the Department of Climate Change at the Ministry of Natural Resources and Environment of Laos, Syamphone Sengchandala, stressed the importance of the project, saying: “This project offers hope for the future by recognising that nature provides some of our greatest defences against extreme weather. The question is whether we can learn to protect these natural services, and this project is a major step forward.”

As the pressure of the climate crisis mounts, communities around the globe are trying to develop new methods to become resilient. Ecosystem-based adaptations are approaches that have shown to be effective in mitigating the effects of the climate crisis, and allow communities to flourish and maintain their livelihoods despite the difficulties posed by it.

Nestled between the hills north of Hong Kong and the breathtaking skyline of Shenzhen lies Deep Bay, semi-encircled by the Ramsar site of Mai Po wetland, a location of significant ecological interest home to numerous species of birds.  

Since the opening of China’s economy in the 1990s, Shenzhen has grown exponentially into a city of almost 13 million people. Deep Bay faces severe environmental threats including water pollution, rising mudflat levels from intense urbanisation and land reclamation on the Shenzhen side of the Bay. Mangrove forests have been cut down and the natural coastline converted into concrete sea walls. But threats to the natural order extend to the sky. The high-rise buildings in Shenzhen Bay are threatening the bird populations that find sanctuary at the Mai Po wetland during the winter season.

Mai Po Bird Species

Every winter, around 90,000 migratory birds seek refuge in the marshes and mudflats of the internationally-acclaimed Mai Po Nature Reserve in Hong Kong. Of the 380 species of birds that inhabit the reserve, 35 are of global conservation concern, including the Saunders’s gull and the black-faced spoonbill. 

Other critters such as otters, fiddler crabs and mudskippers also call the area home, and are the main food source of the waterbird. Hong Kong is situated beneath two major bird migratory pathways, the East Asian-Australasian Flyway and the West Pacific Flyway. Birds with breeding sites in North Asia and Siberia fly to Hong Kong every winter to rest and stay over winter and they fly back to their breeding site in spring. The nature reserve is managed by World Wildlife Fund (WWF) and a bird survey is conducted every winter by the Bird Watching Society (BWS). 

You might also like: Blue Whales are Making a Comeback in the Atlantic

Figure 1. Number of overwinter waterbirds surveyed by the Bird Watching Society

A clear correlation exists between the construction boom that has engulfed Shenzhen and declining bird populations. In particular,  the 2019 BWS annual report shows that the number of birds has decreased since 2008, coinciding with the development of Nanshan and Futian districts in the west and north of Shenzhen Bay, adjacent to the Mai Po Nature Reserve. 

Overall Shenzhen, one of China’s premier shipping and manufacturing centres, is home to 223 completed skyscrapers higher than 150m, giving the city the dubious honour of having the third largest concentration of such infrastructure in the world, after neighbouring Hong Kong and New York City. 

Shenzhen’s construction boom is impressive. In 2008 alone, eight skyscrapers taller than 150m were completed and in 2017 the fourth tallest skyscraper in the world- the Ping An Finance Centre- was completed, standing at 599m tall. More skyscrapers are scheduled for construction, including China’s would-be tallest skyscraper. At 700m tall, the project is expected to be completed by 2023. But the concrete jungle represents a major flight hazard for migratory birds.

How many birds are killed by skyscrapers?

Bird-skyscraper collisions are decimating populations. This phenomenon is known as towerkill; the dynamics of which have been studied in Toronto and New York City. It is estimated that nine million birds die each year due to them mistaking reflective windows for open sky or being dazzled by the bright lights from the skyscrapers at night. 

There are no official studies of towerkill in China but it is estimated that the number of birds killed would be much higher than New York City as the skyscrapers in Shenzhen are more concentrated and the urban area is in close proximity to the wetland that the birds rely on.

Studies show that using ecologically-friendly architectural designs such as specialised glass, window film and external shutters could reduce the glaring from skyscraper windows. Legislation on light pollution would also help reduce the collision of birds. 

Active participation by all could ease this problem. Interactive tools are available that allow citizens to report bird deaths, the data gleaned from which is used to map the relationship between skyscrapers and bird collision and assist urban planners to design more eco-friendly urban areas for birds. 

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