Tag Archives: freshwater biodiversity

Natural Capital and Human Well-Being

What is the contribution of nature to the economy?… The breathable air, drinkable water and tolerable temperatures that allow humans to do everything they do, and the complex ecosystems that maintain them, tend to be taken for granted. Professor Dasgupta’s review on the Economics of Biodiversity does not seek to play on the heartstrings with tales of starving polar bears. Rather, it makes the hard-headed case that services provided by nature are an indispensable input to economic activity. Some of these services are relatively easy to discern: fish stocks, say, in the open ocean. Others are far less visible: such as the complex ecosystems within soil that recycle nutrients, purify water and absorb atmospheric carbon. These are unfamiliar topics for economists, so the review seeks to provide a “grammar” through which they can be analysed.

The report features its own illustrative production function, which includes nature. The environment appears once as a source of flows of extractable resources (like fish or timber). But it also shows up more broadly as a stock of “natural” capital. The inclusion of natural capital enables an analysis of the sustainability of current rates of economic growth. As people produce GDP, they extract resources from nature and dump waste back into it. If this extraction and dumping exceeds nature’s capacity to repair itself, the stock of natural capital shrinks and with it the flow of valuable environmental services. Between 1992 and 2014, according to a report published by the UN, the value of produced capital (such as machines and buildings) roughly doubled and that of human capital (workers and their skills) rose by 13%, while the estimated value of natural capital declined by nearly 40%. The demands humans currently place on nature, in terms of resource extraction and the dumping of harmful waste, are roughly equivalent to the sustainable output of 1.6 Earths (of which, alas, there is only the one)…Indeed, Professor Dasgupta argues that economists should acknowledge that there are in fact limits to growth. As the efficiency with which we make use of Earth’s finite bounty is bounded (by the laws of physics), there is necessarily some maximum sustainable level of GDP…

Professor Dasgupta hints at this problem by appealing to the “sacredness” of nature, in addition to his mathematical models and analytical arguments.

Excerpts from How should economists think about biodiversity?, Economist, Feb. 6, 2021

Choked by Hyacinths: Lake Victoria

The report, Freshwater biodiversity in the Lake Victoria Basin (2018), assesses the global extinction risk of 651 freshwater species, including fishes, molluscs, dragonflies, crabs, shrimps and aquatic plants native to East Africa’s Lake Victoria Basin, finding that 20% of these are threatened with extinction. Of the freshwater species assessed, 204 are endemic to the Lake Victoria Basin and three-quarters (76%) of these endemics are at risk of extinction.

The African Lungfish (Protopterus aethiopicus), for example, is declining in the Lake Victoria Basin largely due to overfishing, poor fishing practices and environmental degradation as wetlands are converted to agricultural land. The lungfish is considered a delicacy for some local communities and is an important local medicinal product, used to boost the immune system and treat alcoholism. The lungfish is also traded at market, making it important to the local economy.

Lake Victoria is the world’s second largest freshwater lake by surface area. Its catchment area includes parts of Kenya, Tanzania, Uganda, Burundi and Rwanda. Also referred to as ‘Darwin’s Dreampond’, Lake Victoria is known for its high levels of unique biodiversity. The Lake Victoria Basin harbours immense natural resources including fisheries, forests, wetlands and rangelands….

Pollution from industrial and agricultural sources, over-harvesting of resources and land clearance are among the primary threats to biodiversity in this region. Invasive species also present an important threat to native biodiversity in the basin, affecting 31% of all species and 73% of threatened species. The purple flowered Water Hyacinth (Eichhornia crassipes) was accidentally introduced to Lake Victoria from South America in the 1980s, and at its peak covered close to 10% of the lake surface in dense floating mats. These mats reduce the oxygen and nutrient availability in the water column, which negatively affects native biodiversity. Opportunities for harvesting and exploiting the Water Hyacinth, for example by using the species as fuel in bio-digesters for energy production, are under investigation.

Excerpts from Livelihoods at risk as freshwater species in Africa’s largest lake face extinction – IUCN Report, IUCN Report, Apr. 30, 2018