Lauantai 19.1.2019 klo 12:20 - Mikko Nikinmaa
Out of the world's area, 71 % is sea and 29 % land (including inland water). Out of this 29 %, about 71 % is habitable. About 50 % of this habitable area is used for agriculture: the area is much larger than that occupied by real forests (36-37 %), scrubland (10 %, much of this is eroded farmland) or urban areas (2 %). Most of the agricultured land is pasture (77 %). Thus, all the crops for human food are cultivated in less than 25 % of the agricultural area.
The absolute amount of land that is used for agriculture is not increasing any more. New land is taken into use more or less in the same area as is lost as cultivated soil becomes infertile. The new cultivated land is mainly obtained through deforestration in the tropics. This means the loss of biodiversity and a decrease of the carbon dioxide sink of the forests.
Although the human population has increased markedly in the past fifty years, the amount of feed per capita has also increased. This has happened via "green revolution", the increased yields per area partly as a result of the use of artificial fertilizers, irrigation, pesticides and high-yield strains of cultivated plants. There are, however, several downsides of the high-efficiency agriculture. First, it depletes the soils, which can become uncultivable. However, even if the fertility of the soil can be maintained with the use of artificial fertilizers, they leach in the inland waters, which are a limiting commodity anyway, and their eutrophication generates all sorts of problems for aquatic life. Irrigation improves the immediate water availability in cultivation, but it leads to overall decrease in ground- and lake water, as seen in Aral lake, Israel and California. Decreased groundwater levels can be one of the reasons for the Californian wildfires. Artificial fertilizers are, further, mined, and easily reached sites are more or less depleted. The use of pesticides is counterproductive, since non-target species are affected. Because of marked insecticide use it has already been suggested, and the results indicate clear correlation, that the decrease of beneficial pollinator populations is caused by the indiscriminate use of insecticides. The above examples indicate that the yield increases of "green revolution" may be temporary, and carry a heavy cost to the environment.
In view of this, it appears that there are three possibilities to decrease the need for inreased agricultural land use. All of these are also important ways to combat climate change. The first is to limit population growth. To do this, especially women's education should be improved. The second is to decrease the number of farm animals, especially ruminants whereby the proportion of agricultural land as pasture fields can be decreased and crop cultivation increased. This will decrease the amount of methane produced. Third, production ofedible plants close to their sites of consumption, e.g., aquaponics in cities, should be encouraged. This decreases transport distances for agricultural production.
Torstai 20.7.2017 klo 13:53 - Mikko Nikinmaa
Fishermen always complain that they are allowed to fish too little and fish biologists have alerted people to the fact that politically decided fishing quotas are too big. If fishing cannot be reduced, several preferred species will become extinct in the next hundred years. The lobbying groups for fishing industry have hitherto been able to convince politicians that putting money in new and effective fishing vessels and having fishing quotas enabling overfishing are good ways of preserving employment - one need not care if preferred fish disappear from nearby areas. With new vessels obtained, e.g. with European Union support, one can have longer fishing journeys than earlier.
It appears that a significant problem with fishing is that the identification of fish by fishermen is poor. If one is approaching the maximum allowed quota for one species, the fish are just marked to be of species, where quotas are not near filling. Giving this type of misinformation varies a lot depending on which country the fisherman is from.
However, even in the interests of fishermen, the fishing quotas should be set on scientific, and not political grounds. Further, the quotas should be followed. And actually, increasing the use of aquacultured fish with land-based feed and effective removal of wastes, is the way forward. All these points are important in order to have fish diversity also for future generations.
Maanantai 3.4.2017 klo 13:06 - Mikko Nikinmaa
Fish is, in principle, health food, and also good in terms of climate change. As insect eating has recently been advocated as an environmentally friendly way of actually eating meat, one needs to point out that from energetic grounds fish eating is just as good. Both insects and fish are ectothermic animals, which convert feed to meat at much higher efficiency than cows or swine, because no energy needs to be wasted to maintaining body temperature.
So, it is good to eat fish, but should it be wild-caught or cultured? The world's seas are heavily overfished. The gloomiest predictions estimate that close to half of commercially fished species become extinct within the next century. Despite the overfishing, several nations and the European Union have given large funds to the development of fishing fleets, and more effective fishing gear. At the same time the same instances have pledged to maintain the biodiversity. So, the actions are in fact opposite to promises and only serve to speed up the decrease of biodiversity. In addition to fishing causing the exctinction of species, the problem with wild-caught fish is aquatic pollution. Most pollutants are taken up and remain in the bodies of fish, because they are hydrophobic, whereby their preferred site is the body and not water. Many of the pollutants further bioaccumulate along the food chain.
So, eating wild fish is, in principle, a worse alternative than eating cultured fish. However, there are several things that make the present aquaculture practises problematic for ecologically responsible fish-eater. First, most cultured fish are carnivorous, and their feed largely consists of fish flour. So, in such a case the big fishing fleets will continue to decrease the fish diversity, now not to get food for humans, but to get resources for feed factories. The only sustainable way is to replace some of the fish flour in feed with plant product. This is a direction to which several fish feed companies have recently gone to. Second, aquaculture causes local eutrophication because of the feed and faeces, which have high amounts of nutrients. The way of prevent this would be to have aquaculture facilities separated from general aquatic environment so that all the water used could be purified. One should here point out that the cultured fish do not produce more faeces than the natural populations - the difference is that they are concentrated in much smaller areas. Third, the use of antibiotics and other drugs in aquaculture facilities is high, because parasites and diseases are much more prevalent in the dense aquaculture populations than in the natural populations. For improvement of situation with regard to this, it would also help, if the aquaculture facilities were separated from natural wateeeeer flow. Also, the use of antibiotics should be discouraged.
In conclusion, it is possible to make aquaculture environmentally friendly, but after that is done, cultured fish will not be the cheapest food that can be found. But we should be ready to use some money to use ecologically sustainable foodstuffs.