Modelling of Nature-Based Solutions (NBS) for Urban Water Management—Investment and Outscaling Implications at Basin and Regional Levels

This manuscript is an attempt to demonstrate effectiveness of nature-based solutions (NBS) and measures to reduce risk of flooding and environmental impact in urban settings. The nature-based solutions (NBS) were assessed as scenarios from experience of urban storm drainage and sewerage systems based on practices that improve urban water management through modelling using urban stormwater management model (SWMM). The model has been applied in a typical urban environment in the second city in Botswana, the City of Francistown, which has a population of more than one hundred thousand. By considering the 2-yr and 10-year storm events in a calibrated SWMM, NBS scenarios from a mix of low impact and drainage measures were considered. The considered NBS scenarios were used to determine their effectiveness in terms of reducing and controlling peak runoff, flood volumes, infiltration and evapotranspiration in the study area, which are vital in assessing the opportunity and challenge for sustainable management of water resources and associated tradeoff of investments in the urban contexts. The study demonstrates the usefulness of implementing effective measures for achieving NBS in urban context and possibility of outscaling at basin and regional levels.

Urban Planning Based on Nature—A Nature-Based Solution

After an international contest announced by the City of Abu Dhabi “Cool Abu Dhabi Challenge”1 and the article published as a digest of a paper titled A Nature-based Solution [1], the decision has been made to take part in improving thermal comfort in public spaces by mitigating the impact of the effect of Urban Heat Islands (UHI)2 in the city of the Belgrade. The basic research aims at achieving the balance between the conflicting impacts when the buildings with their infrastructure and water-green surrounding area are in such correlation that it fulfils acceptable living and heating standards and reduces the use of fossil fuels for cooling the urban areas (buildings). By implementing the remote detection it is possible to analyze and quantify the impact of over-building on the temperature rise in urban areas as well as the disturbance of the heating comfort and the increased demand for additional cooling. Now it is possible to create virtual models that will incorporate this newly-added urban vegetation into urban plans, depending on the evaporation potential that will affect the microclimate of the urban area. Such natural cooling can be measured and adapted and hence aimed at a potential decrease in areas with UHI emissions [2]. Suitable greenery in the summer season can be a useful improvement which concurrently enables and complements several cooling mechanisms—evaporative cooling and evapotranspiration, i.e. natural cooling systems. The remote detection shall establish and map the “healthy” and “unhealthy” greenery zones—that is the vegetation zones with the highest evaporative potential with the “cooling by evaporation” effect and also, by implementing the urban prediction model, it shall propose green infrastructure corridors aimed at a potential decrease in the Urban Heat Island Emission.

Assessing effectiveness of nature-based solution with big earth data:60 years mangrove plantation program in Bangladesh coast

Background In the climate change context,nature-based solution(NBS)is considered one of the effective tools to increase the resilience of socio-ecological system.The concept coincides with the government’s attempts of afforestation and reforestation programs that have been going on for 60 years in Bangladesh.This study,therefore,envisaged understanding how NBS(mangrove afforestation and reforestation)works to promote climate change resilience through the synthetization of remote sensing-based big earth data,statistical tools,and models.The study took the entire coast of Bangladesh except for Sundarbans Reserve Forest and rolled back to 1962 to work on 60 years’time series data.Declassified CORONA satellite imagery along with Landsat satellite imagery was used,which is the first-ever attempt in the remote sensing-based ecosystem work in Bangladesh.Results The study’s main innovation is to spatially establish the effectiveness of the NBS.The study critically assessed and estimated stable lands and their socio-economic benefits as part of the effectiveness of the NBS.As part of the NBS-derived benefits in the context of climate change,it estimated the sequestrated carbon in mangrove forests.A significant positive relationship was observed between the increase of mangroves and stable lands.Near about 448,011 ha of agricultural land was stabilized due to the NBS intervention whose economic value is 18,837 million USD.In addition,29,755.71 kt of carbon have been sequestrated due to NBS program.Conclusions The concept of NBS is still in the development stage and very little or no work has been done so far in measuring and labeling the effectiveness of the NBS.Therefore,our study can innovatively contribute to the scientific community to show the effectiveness of the NBS in three domains(social,economic and ecological)in the changing climatic scenario.

Barriers and Drivers for Mainstreaming Nature-Based Solutions for Flood Risks: The Case of South Korea

Nature-based solutions(NBS)are seen as a promising adaptation measure that sustainably deals with diverse societal challenges,while simultaneously delivering multiple benefits.Nature-based solutions have been highlighted as a resilient and sustainable means of mitigating floods and other hazards globally.This study examined diverging conceptualizations of NBS,as well as the attitudinal(for example,emotions and beliefs)and contextual(for example,legal and political aspects)barriers and drivers of NBS for flood risks in South Korea.Semistructured interviews were conducted with 11 experts and focused on the topic of flood risk measures and NBS case studies.The analysis found 11 barriers and five drivers in the attitudinal domain,and 13 barriers and two drivers in the contextual domain.Most experts see direct monetary benefits as an important attitudinal factor for the public.Meanwhile,the cost-effectiveness of NBS and their capacity to cope with flood risks were deemed influential factors that could lead decision makers to opt for NBS.Among the contextual factors,insufficient systems to integrate NBS in practice and the ideologicalization of NBS policy were found to be peculiar barriers,which hinder consistent realization of initiatives and a long-term national plan for NBS.Understanding the barriers and drivers related to the mainstreaming of NBS is critical if we are to make the most of such solutions for society and nature.It is also essential that we have a shared definition,expectation,and vision of NBS.

Fast action on short-lived climate pollutants and nature-based solutions to help countries meet carbon neutrality goals

Scientific studies show that fast actions to reduce near-term warming are essential to slowing self-reinforcing climate feedbacks and avoiding irreversible tipping points.Yet cutting CO_(2) emissions only marginally impacts near-term warming,This study identifies two of the most ffective mitigation strategies to limit near-term warming beyond CO_(2) mitigation,namely reducing short-lived climate pollutants(SLCPs)and promoting targeted nature-based solutions(NbS),and comprehensively reviews the latest scientifie progress in these fields.Studies show that quickly reducing SLCP emissions,particularly hydrofuorocarbons(HFCs),methane,and black carbon,from ll relevant sectors can avoid up to 0.6℃ of warming by 2050.Additionally,promoting targeted NbS that protect and enhance natural carbon sinks ncluding in forests,wetlands,grasslands,and agricultural lands,can avoid emssions of 23.8 Gt of CO_(2)e per year in 2030,without jeopardizing food security and biodiversity.Based on the scientific evidence,we provided a series of policy recommendations on SLCPs and NbS,including:1)implementing the Kigali Amendment to reduce HFC emissions;2)deploying cost-effective,sector-based measures to reduce methane and black carbon emissions;and 3)implementing targeted NbS to protect and enhance existing carbon sinks and shifting away from forest-burning bioenergy.These fast-acting strategies on SLCPs and NbS will play a key role in securing the most avoided warming in the near-term and help countries meet their mid-century carbon neutrality goals.Finally,we proposed future research topics,including:improving measurement and monitoring systems and techniques for SLCP emissions;developing and improving assessments of marginal abatement costs for SLCP mitigation in dfferent sectors;better quantifying the avoided warming potential from protecting dfferent types of natural carbon sinks by 2030,2050,and over longer periods;and identifying whether there are any biomass types for energy sources that are consistent with the United Nations Environment Assembly's 2022 resolution adopting a definition of NbS.Further research in these areas could help address barriers to adoption and assist countries with better integrating the most effective SLCP and NbS strategies into their climate policies.

基于生物多样性保育的采煤塌陷区生态修复模式

以山东省兖州煤田邹城市太平采煤塌陷区为例,在多年调查研究基础上,分析太平采煤塌陷区新生湿地生物多样性特征及变化趋势,结合动态塌陷特点,重点针对生物多样性保护,探索基于自然的解决方案、以塌陷区新生湿地生物多样性保育为核心的生态修复技术。从生态系统整体设计与修复的角度,提出了6种基于生物多样性保育的采煤塌陷区生态修复模式,包括顺应塌陷时间节律的动态设计、以生境单元为基础的空间结构设计、地形–底质复合设计、水上–水下一体化设计、动物–植物协同设计、多功能生境设计模式,并进行了相关生态修复实践。结果表明,基于生物多样性保育的采煤塌陷区生态修复综合效益明显,修复后的采煤塌陷区成为多样性丰富、多物种协同的共生系统及林–水一体化的动态景观系统,并提供了丰富多样的生态产品。研究结果可为采煤塌陷区生物多样性保护和生态系统修复设计提供科学依据和技术参照。

Do green spaces affect the spatiotemporal changes of PM_(2.5) in Nanjing?

Introduction:Among the most dangerous pollutants is PM_(2.5),which can directly pass through human lungs and move into the blood system.The use of nature-based solutions,such as increased vegetation cover in an urban landscape,is one of the possible solutions for reducing PM_(2.5) concentration.Our study objective was to understand the importance of green spaces in pollution reduction.Methods:Daily PM_(2.5) concentrations were manually collected at nine monitoring stations in Nanjing over a 534-day period from the air quality report of the China National Environmental Monitoring Center(CNEMC)to quantify the spatiotemporal change of PM_(2.5) concentration and its empirical relationship with vegetation and landscape structure in Nanjing.Results:The daily average,minimum,and maximum PM_(2.5) concentrations from the nine stations were 74.0,14.2,and 332.0μg m^(−3),respectively.Out of the 534 days,the days recorded as“excellent”and“good”conditions were found mostly in the spring(30.7%),autumn(25.6%),and summer(24.5%),with only 19.2% of the days in the winter.High PM_(2.5) concentrations exceeding the safe standards of the CNEMC were recorded predominately during the winter(39.3-100.0%).Our hypothesis that green vegetation had the potential to reduce PM_(2.5) concentration was accepted at specific seasons and scales.The PM_(2.5) concentration appeared very highly correlated(R2>0.85)with green cover in spring at 1-2 km scales,highly correlated(R2>0.6)in autumn and winter at 4 km scale,and moderately correlated in summer(R2>0.4)at 2-,5-,and 6-km scales.However,a non-significant correlation between green cover and PM_(2.5) concentration was found when its level was>75μg m^(−3).Across the Nanjing urban landscape,the east and southwest parts had high pollution levels.Conclusions:Although the empirical models seemed significant for spring only,one should not devalue the importance of green vegetation in other seasons because the regulations are often complicated by vegetation,meteorological conditions,and human activities.