碳中和與設計應對策略

“碳中和”是全球熱點議題，其目標設立為后疫情時代推動全球綠色復蘇，實施結構性減排提供了契機。在風險與機遇并存的當下，人類命運共同體聯系日益緊密，“碳中和”發展亦是回應時代新問題新挑戰的重要目標。評估顯示城市在全球排放量中所占的份額超過70%，是全球碳排放的重要貢獻者。隨著預期的人口增長，未來城市減排是實現氣候目標的關鍵解決方案。

早期的人居環境即蘊含“綠色低碳、永續發展”理念。古代西方的庭院中多種植草藥和水果，人們挖掘它們的食用、藥用、美學等功能，并將各種植物功能轉化為生活中所需的元素，這樣可以降低生產成本，并極大地減少食品消費、日常生活的碳足跡；同時，精確計算不同階段不同植物種類的水肥量，注重對植物原始狀態的維護。中國江南地區傳統院落中，“蟹眼天井”的設置不僅解決室內空間的采光通風問題，還可以形成煙囪效應調節熱環境，通過合理利用自然條件減少了大量能源消耗，并結合園林營造形成了經典的“尺幅窗”“無心畫”景致。云南哈尼梯田設計了森林、村寨、梯田、水系“四素同構”的循環系統，維護了鄉土物種資源和生境類型的多樣性，形成了穩定可持續的生態農耕模式，成為可持續低碳稻作人居環境的典范。

碳中和的目標如何在空間場所上實現？如何為數量化的目標賦予形式？這對“雙碳”背景下的設計應對提出了新的挑戰。風景園林師是系統設計師，以公園、林蔭道、雨水花園和生境營造等形式整合綠色基礎設施作為設計策略，不僅可以減碳增匯，還可以管理雨洪、降低城市熱島效應、增加生物多樣性以及改善健康和福祉。同時，設計連續舒適的城市步行環境和綠道系統，整合安全、無障礙的行人和自行車道，倡導公共交通優先，這對減少城市能源需求和降低碳排放、實現更廣泛的城市氣候目標意義重大。

“雙碳”背景下的設計應對策略是要在充分尊重利用自然的生態智慧基礎上，建立全面的知識框架，探索減排增匯在空間上的實現路徑。通過新的設計方式實現碳中和目標所需的新一代公園、綠地、步行騎行交通和公共基礎設施，將不同的城市生態系統融入綠地與公共空間體系中以最大化儲存碳，提高城市應對氣候變化帶來的各類風險的能力，實現城市綠色有機更新；在這個過程中，需要風景園林師科學地考慮各類生態系統的區域配置和與各類服務功能的結合。在面對碳循環失衡的問題時，更加重視城市綠地全生命周期階段的碳平衡狀態，挖掘氣候變化減緩與適應之間的協同效應，強化綠色生態空間在節能減排、碳匯增效、生物多樣性保護、城市更新發展等工作中發揮的重要作用。

在全球氣候變暖的大背景下，碳中和與生態環境是未來長期的研究熱點與重大挑戰，如何發揮多學科交叉優勢，創新設計方法與技術，進一步拓展與延伸生態賦能碳中和的深度，是風景園林學科在實現碳中和目標中的重大使命，也是設計師重新認識自然、思考可持續發展新范式，為未來人居環境建設描繪更加生態、宜居、低碳藍圖的宏觀愿景。

Carbon Neutrality and Design Strategies

Being a global hot-spot issue, carbon neutrality aims to provide an opportunity for promoting global green recovery and structural to promote global green recovery and structural emission reduction in the post epidemic era.In face of co-existence of risks and opportunities today,humanity is increasingly a community with shared future.Carbon neutrality is an important goal in response to new issues and challenges in the new era. Estimates show that cities are significant contributors that account for more than 70%of global emissions. With the expected population growth,urban emission reduction will be the key solution to achieving climate goals.

The early living environment had carried the concept of “green, low-carbon and sustainable development”. Herbs and fruits were planted in ancient Western courtyards. People explored their esculent, medicinal and aesthetic properties,and transformed plants into needed elements needed in life based on their properties, thus lowering production costs and greatly reducing carbon footprint of food consumption and daily life. At the same time, the amount of water and fertilizer needed by different species of plants at different stages was calculated accurately, with emphasis on maintenance of their original state. In the traditional courtyards in Southern China,“crab eye patios” not only solved the lighting and ventilation problems in indoor space, but also created a chimney effect to regulate the thermal environment, which reduced a large amount of energy consumption through rational utilization of natural conditions, and formed classic enframed sceneries through garden design. Hani Terrace in Yunnan province was designed with a four-element isomorphic circulation system consisting of forest, villages, terrace and water. It maintained the diversity of local species and habitat types and formed a stable and sustainable ecological farming model, being model of sustainable low-carbon rice-farming human settlements.

How to achieve carbon neutrality in spaces and places?How to create a form for quantitative goals? This poses new challenges to the design under the background of carbon peaking and carbon neutrality. Landscape architects are system designers. By following the design strategies of integrating green infrastructure through creation of parks, boulevards,rain gardens and habitats, they can help not only reduce carbon emissions and increase carbon sinks, but also manage rains and floods, reduce urban heat island effect, increase biodiversity and improve health and well-being. Furthermore,the design of a continuous and comfortable urban pedestrian environment and greenway system, the integration of safe and barrier-free pedestrian and bicycle lanes, and encouragement of priority of public transport are of great significance to reducing urban energy demand and carbon emissions, as well as achieving broader urban climate goals.

In the context of carbon peaking and carbon neutrality,the design strategies should aim to establish a comprehensive knowledge framework and explore the path to carbon emission deduction and increase of carbon sinks in space based on the fully respect to and utilization of the ecological wisdom of nature. New designs will help probe into the requisite new generation of parks, green spaces, pedestrian and cycling transportation and public infrastructure for carbon neutrality and integrate different urban ecosystems into the green spaces and public space system to maximize carbon storage and improve the ability of cities to cope with risks brought by climate change, thus realizing organic renewal of cities. In this process, landscape architects are required to scientifically take into account regional configuration of various ecosystems and combination of various service functions. In view of the imbalanced carbon cycle, it’s required to pay more attentions to the carbon balance in the whole life cycle of urban green space, identify the synergistic effect between climate change mitigation and adaptation, and strengthen the important role of green ecological space in energy conservation and emission reduction, carbon sink efficiency, biodiversity protection,urban renewal and development, etc.

Against the backdrop of global warming, carbon neutrality and ecological environment will be long-term research hot spots and major challenges in the future. As to how to give full play to the advantages of interdisciplinary,innovate methods and techniques in design practice, and further deepen and extend the depth of ecology-empowered carbon neutrality, it is a major mission of landscape architecture in achieving carbon neutrality, as well as a macro vision of architects in re-understanding of nature,consideration of new paradigm of sustainable development,and depicting a blueprint of more ecological and more livable low-carbon living environment in the future.

Editor-in-Chief: Professor ZHENG Xi

April 28, 2022