Orange News: People have transformed the global landscape by clearing vegetation and reducing the extent of natural habitats, with consequential depletion of plant and animal populations; the replacement of complex ecosystems by simplified human-dominated agricultural or urban environments has caused significant biodiversity loss. At the same time, fossil fuels that power town and cites, and ensure high food yields through mechanization and fertilizer applications on farmland, have increased atmospheric CO2 concentrations, driving climate change.
Until recently, global warming and biodiversity loss have been discussed and addressed separately — they are the subject of different international Conferences of the Parties. But there is a growing realization that climate stabilization cannot be achieved without biodiversity preservation, because protecting or restoring ecosystems and the biodiversity they sustain can help prevent or reduce carbon emissions. On the other hand, global warming is already impacting those plants and animals that cannot adjust their life cycle or physiology to a shifting climate. However, win-win outcomes may be possible. For instance, preserving forest and planting trees increases photosynthetic removal and storage of CO2 from the atmosphere, carbon, while providing habitat for animals and allowing them to fulfill their ecological roles. This is one example of the broad category of ‘nature-based solutions’ to environmental problems — such as climate change. It illustrates how preserving or restoring biodiversity can help stave off climate change.
Hong Kong has a goal of net-zero carbon emissions by 2050, but currently relies on imported gas, coal and oil for its energy supply; natural gas is the most important of these, and is expected to increase in importance. Although gas emits less CO2 than oil, and far less than coal, a large-scale shift away from fossil fuels to renewable energy sources will be essential to meet our net zero goal. Offshore wind farms have repeatedly been advocated by energy experts as a potential solution given local land shortages. Unfortunately, plans for such farms in the southwestern and eastern waters appear to have stalled.
Could nature-based solutions help? Around 1000 years ago, the landscape of Hong Kong SAR would have been covered by tropical forest. All that remains currently are the patches of secondary forest that have regenerated since the Japanese occupation eight decades ago, managed fung shui woods, and areas of plantation that mainly comprise non-native trees. In many places, there is potential to plant trees and restore forest; the more trees planted, and the larger that they become, then the more carbon they store. This is not to say that Hong Kong can keep on burning fossil fuels, but it does mean that some of delay in making the eventual transition to non-renewables might be offset by forest-mediated carbon storage.
While preserving biodiversity can slow or mitigate climate change, climate change itself poses a significant threat to biodiversity. Its effects are aggravated by human alteration or degradation of landscapes that fragments natural habitats, obstructing the range shifts animals must make to compensate for higher temperatures. In addition, when habitat quality is impaired by pollution, it results in conditions that are less suitable for native species, whereas invasive species that humans have introduced from elsewhere tend to be more tolerant of degraded conditions. Many of them flourish as temperatures warm, depriving native species of space, food and other resources. In short, there is positive feedback between the effects of climate change and other human impacts on biodiversity and ecosystems. The fact that damaged or degraded ecosystems absorb less carbon dioxide from the atmosphere, reducing their capacity to slow climate change, is another factor contributing to this positive feedback.
The severity of the effects of climate change on local biodiversity were made clear at a recent community-based workshop organized to give input to HKSAR Government that is now preparing its second Biodiversity Strategy and Action Plan (BSAP). The new BSAP is expected to be published in 2025 but, unlike on the first version promulgated in 2016, it will not involve the formal participation of a variety of local experts in the drafting process but will be produced in-house by government before any public consultation is invited.
Prof. Jimmy C.H. Fung of HKUST briefed participants about potential climate futures for Hong Kong, including hotter temperatures, longer, more frequent and intense heatwaves, as well as more intense rainfall and extreme weather. But what will this mean for biodiversity? The short answer is that we cannot be sure. But as climatic conditions diverge from those to which local species have historically been adapted, the consequences are hardly likely to be positive. To give one example: The Giant Spiny Frog is currently confined to upland streams on Tai Mo Shan. To compensate for a hotter climate, these amphibians will have to shift their ranges to cooler sites uphill. Whether they can do this fast enough, or whether there is enough suitable high-altitude habitat for them is not known.
At this critical time in Hong Kong’s development, when we need to take decisive action to achieve our zero-carbon goals, the new BSAP must include urgent measures to restore and protect biodiversity so as to mitigate the impacts of climate change. We cannot wait: for instance, it will take time for newly planted trees or restored forest to achieve their full potential to absorb CO2 and slow rates of global warming. Climate change and biodiversity loss are dual emergencies that are ongoing, inextricably linked, and certain to get worse; failure to deal with either one decisively could collapse the life-support systems on which we all depend.
Originally published on Orange News on 26 Jul 2024. Written by David Dudgeon.
