NBS References

• Extensive tree planting is widely promoted in Africa with the AFR100 targeting 100 million hectares of land for restoration, however this is based on erroneous assumptions that grassy biomes are deforested and degraded

• NETs may not actually be effective as there could be negative climate effects such as changed in albedo

• There needs to be a huge amount of money and work over a large scale for this to be effective

• Grassy biomes are often better at conserving forest and water resources than plantations, these schemes may distract from the real need to decrease fossil fuel reliance

Bond et al., 2019

• Better stewardship of land is needed to achieve the Paris Agreement, the use of NCS can provide around 37% of cost effective CO2 mitigation needed by 2030

• Around half of the maximum NCS potential is cost effective, but this should not delay action on reducing fossil fuel emissions

• Specifically important pathways are forest, reforestation, avoided forest conversion, improved forest management, agriculture and wetlands

• These do face challenges such as uncertainties, barriers to implementation, climate change feedbacks and unfocused policy

Griscom et al., 2017

• NBS works with and enhances nature to mitigate or adapt to climate change while simultaneously providing benefits to biodiversity and people; it has a huge range of co benefits

• We live in a time of environmental challenge but also opportunity, specifically the post-EU window allows for new policy to be developed that focuses on the importance of NBS

• NBS can stimulate green employment and boost human health and wellbeing but better assessment frameworks and evidence will be needed to ensure this

• Key NBS comes from peatlands, woodlands, salt marshes, arable landscapes and urban street trees

Stafford et al., 2021

• The UK has one of the lowest levels of woodland cover of any European country, the England Tree Strategy hopes to expand trees and woods to tackle nature and climate crises

• Well located tree cover has the potential to reduce risks of flooding, filter pollutants, create jobs, provide sustainable timber and improve human health

• The scale of return on investment will require trees to be planted in the right places to maximise co-benefits

Mann, 2020

• Flood risk and associated impacts are major concerns following widespread flooding in the UK in December 2015, this saw attention turned from hard engineering solutions to soft engineering

• Tree cover could increase the storage capacity of catchments, increase lag time, reduce water discharge and reduce flood risk particularly in smaller catchments

• There is little direct evidence for this as well as unpredictability of the weather and potential for adverse effects justifying weak flood protection policy and action

Carrick et al., 2018

• Storms are no longer isolated events due to climatic change with relentless rainfall devastating lives and properties

• Climate change increases the likelihood of extreme rainfall to see flooding become a significant risk to the UK

• Trees can aid in reducing food risks due to canopy cover, roots, urban trees and deadwood and dams but we need more

Woodland Trust, 2024

• Climate change will alter long term provisions of goods and services people obtain from the land due to temperature rises, heavy rainfall and reduced water availability in summer

• Current policies and low-regret adaptation actions may not be sufficient, more transformative actions are needed accompanied by awareness and meaningful long-term planning 

• There will be short-term costs but also long term benefits, anticipatory land use changes are the most cost effective

Committee on Climate Change, 2018

• As urban populations grow and cities magnify the impacts of climate change, mitigating and adapting to climate change in urban areas becomes increasingly important 

• NBS are more flexible, multi-functional and adaptable than traditional approaches

• Cities face challenges such as sea-level rise, coastal storms, extreme heat, water security, inland storms and pluvial flooding that are exacerbated by the urban heat island effect and highly impervious surfaces

• NBS can aid in adapting to these issues, but more research is needed into its effectiveness, costs and benefits and equity in terms of distribution of these solutions

Hobbie & Grimm, 2020

• Forests must play a part in removing vast amounts of CO2 from the atmosphere, they could store enough carbon to limit global warming to 1.5 degrees but this would require adding up to 24 million hectares of forest every year until 2030

• The regeneration of natural forests must be prioritised and this must have tighter definitions, transparent reporting and outcomes that state tradeoffs

• The most effective place to plant trees is in the tropics and subtropics and this must be natural regeneration through protecting the land from disturbances to allow trees to return and flourish as well as being protected

• Plantations and agroforestry are not as effective due to planting of monocultures and too smaller scales

• Bioenergy with CCS can also be used alongside natural forests in order to limit warming to 1.5 degrees

Lewis et al., 2019

• Biodiversity increases ecosystem resilience for a broad range of climatic events including wet or dry, moderate or extreme and brief or prolonged 

• Productivity of low-density communities changed by 50% during climatic events by high diversity communities changed by only 25%

• Recovery was not impacted by biodiversity levels showing it stabilises productivity 

• Anthropogenic environmental changes driving biodiversity loss are likely to decrease ecosystem stability; conversely, restoration could restore it

Forest et al., 2015

• High levels of biodiversity acts as insurance against environmental fluctuation acting as a buffer and stabilising influence

• There is a minimum number of species essential for ecosystem functioning and a larger number is needed to maintain stability in changing environments in order to ensure biogeochemical stability

• Biodiversity also allows for multi-functionality of ecosystems

Loreau et al., 2001

• Restoration and rehabilitation projects are key to recovering services, goods and resources ecosystems offer to humankind

• Man-made solutions are high-maintenance, costly and ineffective over longer time periods as they depend on external inputs of energy, money, management and control 

• NBS are more sustainable and superior in land management as they use natural flows of matter and energy, take advantage of local solutions and follow seasonal and temporal changes as well as having co-benefits to the sustainable economy and society of a region

• Soil-vegetation solutions enhance soil health and functions whilst landscape solutions focus on connectivity 

• By reducing connectivity of the landscape less rainfall can be transformed into runoff and flood risk, droughts and erosion problems are reduced

Keesstra et al., 2018

• Private companies now use trees as a marketing tool to offset their environmental impacts as well as empowering local people and women in their endeavours but often this is simply corporate greenwashing 

• Often monocultures replace diverse forests due to growing fast, but they do not form the same biodiversity; the wrong species can often be chosen with adverse impacts

• Tree planting schemes require management, if not cared for they will die but they are often abandoned after planting 

• Planting on sites without consulting local communities, ignoring customary land rights and management schemes may exacerbate socio-political tensions

• Companies must care about communities instead of their own reputation and careful consider tree planting

Neimark, 2018

• Pledges from countries and the Bonn Challenge are revealed to aim to restore 292 million hectares of degraded land but 45% of this will be plantation monocultures, 21% agriculture and only 34% restoring natural forests 

• If the whole 350m ha was natural forests this would remove 42 billion tonnes of carbon by 2100 but the current pledges relying on plantations reduce this to 16 billion

• Land set aside for natural forests holds 40x more carbon that plantations due to removing carbon for many decades whereas plantations are harvested and crops decompose

• Meeting the Paris Agreement will require 200 billion tonnes to be removed by 2100 so we must reduce emissions enough to not need to use huge amounts of land for forest restoration

• Newly restored natural forests must be protected in order to avoid bioenergy demands destroying them; definitions must be coherent and exclude monoculture plantations

Lewis & Wheeler, 2019

• Petlands are a globally significant store of carbon covering 3% of the Earth’s surface and storing over 600 Gt of carbon; over 90% of this is stored in northern peatlands 

• In the UK in the 1950s and 1980s approximately 9% were drained for forestry and 17% in Scotland

• Many Norway spruces and Scots pine species were planted due to being good candidates for the high water tables, there were monocultures planted of these non native species with adverse effects of drying out peat and releasing carbon when harvested; the non-native conifers could lead to carbon losses

• There is a need for more UK specific evidence on the effects of conifer planting on peat bog storage

Sloan et al., 2018

• A warming climate is expected to have an impact on the magnitude and timing of European river floods 

• Warmer temperatures have led to earlier spring snowmelt floods throughout northeastern Europe

• Delayed winter storms associated with polar warming have led to later winder floods around the North Sea and some sectors of the Mediterranean coast 

• Earlier soil moisture maxima have led to earlier winter floods in western Europe

Blöschl et al., 2017

• Extreme cold and hot temperatures increase mortality rates, especially for the elderly; the relationship is flattened by higher incomes and adaptation 

• Global increase in mortality risk to climate change is valued at roughly 3.2% of global GDP in 2100 under a high emissions scenario; cold locations are projected to benefit but poor and hot locations have large damages

Carleton et al., 2021

• Anthropogenic climate change forms an array of impacts such as sea-level rise, climate variability, droughts, floods and wildfires with severe social and economic consequences particularly in low and middle income nations

• Prevailing approaches have relied on hard engineering but NBS can complement and improve on these as they have  range of co-benefits flowing from healthy and resilient national ecosystems

• They have become more prominent in international policy such as IPCC 2019 report, WEF, UNFCCC and emphasised in the Paris Agreement

• They can be effective but there must be more investigation into the most vulnerable communities in the Global South and their broad  outcomes compared to alternatives

Chausson et al., 2020

• Combined approaches to coastal adaptation are important due to the uncertain and multiple coastal stressors the environments face, promoting more versatile strategies is key to increasing resilience 

• Traditional engineering often involves removing and replacing natural ecosystems but ecological engineering aims to consider the people and the environment to emphasize positive interactions and generate synergies to protect ecosystem services

• Marshes reduce wave action, facilitate deposition of sediments to keep up with sea-level rise and use expansive root systems to decrease shoreline erosion with co-benefits to fishery production, carbon sequestration and human economic sectors

• Mangroves alleviate moderate tsunami waves and use roots to trap sediments to protect against sea level rise with co-benefits of increased local employment, breeding fish and regulating rainfall patterns

• Oyster reefs also protect shorelines by reducing wave energy and erosion as well as creating fish habitats and improving water quality

Cheong et al., 2013

• Mangroves provide flood protection benefits exceeding $US 65 billion per year and if they were lost 15 million more people would be flooded annually around the world

• The nations that received the greatest economic benefits including the USA, China and Mexico and the nations receiving the greatest benefits in terms of people protected are Vietnam, India and Bangladesh 

• Mangroves have great value as natural coastal defences at many scales which informs incentives for conservation and restoration in development, climate adaptation, disaster risk reduction and insurance

Menendez et al., 2020

• The GGW is a restoration effort to half land degradation across Africa, it has great geographical scope, financial investments, stakeholder involvement and occurs in a window of opportunity 

• When it was first designed it was a ‘wall of trees but now is a mosaic comprised of diverse landscape actions designed to provide long-term solutions for improving environmental and socio-economic conditions

• A key success has been seen in Niger as farmer led natural generation of trees has enhanced resilience to droughts as well as improving economic resilience as the majority of the population rely on agriculture for their livelihoods

• The GGW has other co-benefits such as the development of women-run communal vegetable gardens in villages and new water access points created

• There must be specific research done as shifts in competition of vegetation in Burkina Faso and Senegal have negatively impacted local livelihoods due to multifunctional species and larger trees being lost as well as their ecosystem services to the communities

Goffner et al., 2019

• In Slovenia a 70km2 catchment has rewilded over 70% in 50 years to improve soil quality, biodiversity and sequestration as well as reducing flood risks and erosion

• In Iceland the SCSI have worked in Rangarvellier to restore soils with the result of decreasing discharge peaks, decreasing groundwater depletion rates and decreasing erosion rates

• Grassed waterways are used to filter sediment from water in Ethiopia, before this grass strops and soil/stone bunds were used

• In Augustenborg in Sweden trenches, ditches, ponds and wetlands as well as green roofs have been implemented to reduce runoff, increase biodiversity and bring about socio-economic improvements

Keesstra et al., 2018

• ‘Million Trees LA’ program efforts began in 2006 to plant one million trees across the city in order to challenge the urban heat island effect caused by large expanses of concrete and low vegetation cover interacting with the hot, dry climate

• The increased tree canopy led to reductions of 3-4 degrees in shaded areas, saved around $10 million due to reduced air conditioning needs and reduced heat disparities between wealthy and lower-income neighbourhoods

McPherson et al., 2011

• Intensive development of residential areas in Polish cities began in 1990 and in 1974 a law mandating substantial green areas in multi-family housing was discontinued with current regulations focusing on a ratio of biologically vital areas (RBVA), a minimum of 25% for multi-family estates

• Developers use features such as green roofs and green car parks to technically meet legal requirements whilst maximising building density

• The elements are implemented more for compliance than ecological benefit with no real attention paid to delivering real ecological benefits to biodiversity or ensuring public access

• A lack of urban planning leads to fragmented land parcels and gated communities further limit access to green areas intensifying social exclusion and spatial inequality

Galecka-Drozda et al., 2021