![]() ![]() This “safe boundary” has already been exceeded on a third of the world’s land by hydroelectric dams, drainage systems and construction. The benchmark for surface water is that no more than 20% of the flow of rivers and streams should be blocked in any catchment area because this leads to declining water quality and habit loss for freshwater species. This is an issue of social justice because poorer, often predominantly black communities tend to suffer the worst results as many are found in vulnerable areas. At a local level, for example in cities, it follows the World Health Organization in establishing a boundary of 15 micrograms per cubic metre mean annual exposure to small particulate matter, known as PM2.5, which can damage the lungs and heart. At a global level, the report has focussed on minimising the imbalance of aerosol concentrations between the northern and southern hemispheres, which can disrupt the monsoon season and other weather patterns. However, about two-thirds of altered landscapes fail to meet this goal.Īnother target is for aerosol pollution, which accumulates from car exhausts, factories, and coal, oil and gas power plants. In human-altered areas, such as farms, cities and industrial parks, the commission says at least 20 to 25% of the land needs to be devoted to semi-natural habitats such as parks, allotments and clusters of trees in order to maintain ecosystem services such as pollination, water quality regulation, pest and disease control, and the health and mental health benefits provided by access to nature. The reality, however, is that only 45to 50% of the planet has an intact ecosystem. To achieve this, the “safe and just” boundary is for 50to 60% of the world to be home to predominantly natural ecosystems. They note it is impossible to stabilise the climate without protecting ecosystems. They say a safe and just climate target is 1C, which would require a massive effort to draw carbon dioxide from the atmosphere. The Earth Commission notes that this is a dangerous level because many people are already badly affected by the extreme heat, droughts and floods that come with the current level of about 1.2C. ![]() For climate, the world has already adopted a target to keep global heating as low as possible between 1.5C to 2C above pre-industrial levels. Setting global benchmarks is challenging. The situation is grave in almost every category. The boundaries are based on a synthesis of previous studies by universities and UN science groups, such as the Intergovernmental Panel on Climate Change and the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services. Instead of pulse, temperature and blood pressure, it looks at indicators such as water flow, phosphorus use and land conversion. The study sets out a series of “safe and just” benchmarks for the planet that can be compared to the vital signs for the human body. It hopes that cities and businesses will adopt the targets as a way to measure the impact of their activities. The Earth Commission, which was established by dozens of the world’s leading research institutions, wants the analysis to form the scientific backbone of the next generation of sustainability targets and practices, which extend beyond the current focus on climate to include other indices and environmental justice. We are approaching tipping points, we are seeing more and more permanent damage of life-support systems at the global scale.” “We have reached what I call a saturation point where we hit the ceiling of the biophysical capacity of the Earth system to remain in its stable state. Prof Johan Rockström, one of the lead authors, said: “It is an attempt to do an interdisciplinary science assessment of the entire people-planet system, which is something we must do given the risks we face. The study, which was published in Nature on Wednesday, is the most ambitious attempt yet to combine vital signs of planetary health with indicators of human welfare.
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