Ciò che le imprese e le città devono fare per rimanere entro limiti ambientali "sicuri e giusti" per il carbonio, l'acqua, i nutrienti, la terra e altre risorse naturali è oggetto di una nuova serie di raccomandazioni degli esperti della Commissione per la Terra.

Gli autori, provenienti da istituzioni accademiche tra cui la University of Exeter Business School, hanno pubblicato sulla rivista Nature le principali lacune di conoscenza per i ricercatori per aiutare le città e le imprese a operare entro i limiti del sistema Terra .

Precede un rapporto della Commissione per la Terra che uscirà il prossimo anno che delineerà una serie di "confini del sistema terrestre" (ESB) basati sulle ultime valutazioni scientifiche, modellistiche e bibliografiche.

Dieci anni fa, gli scienziati hanno definito una serie di confini planetari entro i quali l'umanità può operare "in sicurezza" in nove aree:cambiamenti climatici, biosfera, nutrienti, acqua, uso del suolo, acidificazione degli oceani, esaurimento dell'ozono, aerosol e nuove entità e presto -gli ESB da definire aggiungeranno una dimensione di giustizia sociale, per garantire che i confini quantificati siano "giusti" oltre che "sicuri".

I ricercatori sostengono che è necessario sviluppare metodi per identificare ciò che le città e le aziende devono fare affinché il mondo rimanga all'interno degli ESB e per aiutarli a valutare la loro quota di responsabilità nei confronti dei bilanci globali di carbonio, acqua, nutrienti, terra e altre risorse naturali, e fissare obiettivi per proteggerli.

Gli autori sostengono "obiettivi basati sulla scienza" e affermano che gli obiettivi devono essere "misurabili, attuabili e limitati nel tempo", sottolineando che poche città e aziende hanno attualmente obiettivi basati sulla scienza e delle prime 200 città con le emissioni più elevate, solo 110 hanno impegni "net zero" in linea con l'accordo di Parigi.

L'autore principale Xuemei Bai, Distinguished Professor presso la Fenner School of Environment and Society presso l'Australian National University e membro della Commissione per la Terra, afferma che "è un lungo raggio, ma l'umanità deve rimanere entro i budget limitati del nostro pianeta. Sviluppo scientificamente robusto e metodi socialmente giusti per allocare le risorse naturali e le responsabilità sono essenziali per rispettarle."

"Città e aziende sono i principali contributori ai cambiamenti a livello planetario, ma anche attori chiave per le soluzioni. Esistono lacune di conoscenza su come tradurre tali confini in allocazioni concrete per le imprese e le città e le nostre raccomandazioni cercano di colmare tali lacune."

La coautrice Gail Whiteman, professoressa di sostenibilità presso l'Università di Exeter Business School, afferma che il loro "lavoro costituisce un valido motivo per azioni congiunte rivoluzionarie da parte di aziende e città per affrontare sinergicamente i punti caldi urbani all'interno dei confini del sistema terrestre utilizzando limiti basati sulla scienza. In questo momento , corporate and urban targets are siloed. A key next step is for initiatives like the International Sustainability Standards Board and the Science Based Targets Network to integrate ESBs and encourage joint action."

Co-author Johan Rockström, co-chair of the Earth Commission and director of the Potsdam Institute for Climate Impact Research, says that "Earth system boundaries are linked, so targets need to be aligned. Measures that focus on one domain can be beneficial or detrimental to others."

"Climate change, for instance, depends on land-based processes—such as methane emissions from thawing permafrost and weakened carbon sinks through deforestation. Several pressure points can combine so that tipping points are reached sooner."

Co-author Şiir Kılkış, senior researcher at the Scientific and Technological Research Council of Turkey says that "cities exchange people, energy and goods with their local and global hinterlands. The top 200 cities with the largest greenhouse-gas emissions also host the headquarters of 360 of the top 500 emitting companies."

"Looking across domains, more than 50% of these cities and companies are in water-stressed areas, including Mexico City, Santiago, Beijing, Madrid, New Delhi, Rome, Istanbul in Turkey and Phoenix, Arizona."

Co-author Anders Bjørn, postdoctoral fellow at the Technical University of Denmark says that "it is encouraging that more and more companies are setting reduction targets for carbon emissions based on the 1.5-degree Paris goal. These science-based targets are typically more ambitious than national commitments and should inspire more action from policymakers at different levels. Now we need the biggest emitters and resource consumers to step up and do their part in limiting climate change and protecting all other Earth system boundaries."

Erin Billman, Executive Director of Science Based Targets Network advised that "Earth Commission's critical work on Earth system boundaries is directly informing Science Based Targets Network's development of environmental science-based targets (SBTs) for companies and cities, which build upon climate SBTs to cover freshwater, land, ocean and biodiversity."

The authors highlight seven recommendations for researchers aiming to translate ESBs into concrete steps for cities and businesses.

1. Develop common procedures

Principles and protocols must be developed, and methods, metrics, assumptions and uncertainties must be clear. Without such clarity, cities and companies may seek to minimize their own responsibility and maximize the resources they claim; powerful actors may exert undue influence.

2. Focus on interactions

Earth system boundaries are linked, so targets need to be aligned. Climate change, for instance, depends on land processes—from methane emissions from thawing permafrost to weakened carbon sinks through deforestation. Researchers should identify key activities that span several ESBs and evaluate what can be achieved by targeting them.

3. Acknowledge dynamics

Most targets focus on a particular date, like 2030 or 2050. But pathways are important. For example, reducing carbon emissions linearly to net zero by 2050 would result in less warming than keeping them high for the next decade and then dropping suddenly. Researchers must develop an agile approach—time-sensitive and dynamic goal setting that allows regular checking, adjustment and updating.

4. Allocate for justice and equity

Targets need to reflect socioeconomic contexts, such as income and consumption levels, environmental impacts or capabilities to act. For example, cities with high consumption levels, historical emissions or high revenues should arguably adopt more stringent targets than others.

5. Support monitoring and accountability

Much work needs to be done to support monitoring and accountability. We recommend that initiatives, such as the new International Sustainability Standards Board, engage with cross-disciplinary scientists to ensure that their proposed "global baseline of sustainability-related disclosure standards" explicitly link cities and companies with ESBs. Independent auditing systems are also needed.

6. Establish governance mechanisms

New policies and regulations will be needed to incentivize or mandate cities and companies to adopt targets. One approach is to recognize each of the ESB domains as a global commons. For climate change, the United Nations could initiate intergovernmental panels and call on governments to mandate science-based target setting for large cities and companies. There is no guarantee this would fix the problem, but it would put ESBs onto the policy agenda.

7. Design incentives

Widespread adoption of science-based target setting by cities and companies is essential, as they can also prompt and incentivize national governments to follow the suit. Quality trademarks for products and services, such as "kitemarks" or positive labels, could be issued to raise awareness and encourage others. Financial incentives should be scaled up and expanded. + Esplora ulteriormente

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