Decreased oil use influences climate change in two ways

Keskiviikko 8.6.2022 klo 20:22 - Mikko Nikinmaa

Oil spills are among the biggest toxicological problems in marine environments. Although the news pictures invariably show oil-covered birds, which die of heat loss in water, oil components are also very toxic to all aquatic organisms. The decrease in the use of fossil fuels will decrease the tanker transport of oil, oil leaks in the harbours of oil refineries, and accidental or intentional oil spills from ships. The net result is that oil pollution will diminish. Although only the importance of oil burning is usually considered as being important in combatting climate change, the decrease in oil pollution must also be considered. The fact is that marine algae carry out about half of the carbon dioxide removal and oxygen production by photosynthesis. Algal photosynthesis has decreased by 10-20 % because of marine pollution. This decrease is so far greater than what has been caused by deforestation of rainforests. The main pollutant causing algal deaths is oil and its components. Thus, decreasing the oil use will combat climate change not only directly but also as decreased oil pollution enables algal photosynthesis to recover. As a consequence, oil ban will have greater positive effect on climate than expected from decreased carbon dioxide production because of oil burning.

Kommentoi kirjoitusta. Avainsanat: aquatic toxicology, oil pollution, algal photosynthesis

Environmental Effects of Shipping

Keskiviikko 15.1.2020 klo 15:44 - Mikko Nikinmaa

Close to 70 % of all trade is transported waterborne. In terms of carbon footprint this way of transport is much better than air or road traffic, but there are still several environmental consequences. In addition to carrying cargo, cruises are becoming more and more popular form of tourism. Currently, cruise ships (including ferries) constitute close to 15 % of the world’s total fleet. The environmental consequences of shipping have been reviewed by Jägerbrand et al. (Science of the Total Environment 695, 133647, 2019).

The first environmental problem is the use of marine heavy fuel oil as a source of energy in ships (and petrol in small boats). While the total fuel consumption is only a very small percentage (less than 0.5 %) of total oil use, the fuel has until recently contained very high sulphur oxide concentrations, so that at the time that European and American land-based industries and power plants have been required to remove sulphur oxides from their smoke because of the acid rain problem of 1970’s and 1980’s the ship fuel use has contributed 10-20 % of the world’s sulphur dioxide emissions. Now that European Union has put an upper limit to the allowed sulphur concentration first in the Baltic anIMG_20170802_0109.jpgd North Sea, because of their heavy shipping, the Finnish shipping companies and industries were screaming that such an increase in the transport costs (low-sulphur fuel oil is more expensive than high-sulphur one or alternatively removing sulphur dioxide from fumes cost). However, the EU directive has been in effect a couple of years now, and has not resulted in serious economic disturbances (this incidence, to me, shows the hypocrisy of environmental thinking of many policy makers, as soon as any imagined expenses are increased because of environmental actions, they cannot be tolerated). The World Maritime Organisation is now putting an upper sulphur limit to all maritime heavy fuel oil. But in the long run, one should be able to go to oil-free shipping. Effective wind turbines are developed, and some ships using them may soon sail in the world’s seas. With the use of oil, there are several types of oil spills. Although the shipwrecks with pronounced oil leakage have decreased, most harmful spills are ones in small scale: washing empty oil tanks, using lubricating oils etc. It doesn’t help the seabird losing its insulation and dying of hypothermia knowing that the spill was small.

Another traditional big problem has been the use of antifouling paints on ships. They are used to prevent the growth of organisms on ships, both barnacles and algae. The growth of organisms on ship hulls can increase fuel consumption more than 10 %. Because very different types of organisms are tergeted, the toxic agents must kill all forms of life. Tributyltin (TBT) chloride was initially the common toxic agent, because it was very toxic, but considered to break down in weeks. However, it was noticed in 1980’s that TBT caused imposex (females developed male penis and became infertile) in molluscs near boat harbours. This led to a complete ban of the compound, but it persist in anoxic sediments for tens of years, and there are consequently still toxic TBT concentrations in narrow and shallow shipping routes. The next generation of antifouling paints has used copper ion as the toxic compound. To increase the paint’s toxicity to photosynthetic organisms, herbicides such as diuron are added. Presently, it appears that leaching from the ship paints is the major source of copper in aquatic environment. Further, the problem that cannot be avoided is that antifouling paints must kill everything.

Another problem with ships is that their waste has been disposed to sea with “out of sight out of mind” mentality. This has included both toilet wastewater and solid waste. While in most cases the waste load is very small in comparison to the waste coming from land, the increased cruising activity in Arctic and Antarctic has made the waste from ships a major cause of pollution in these vulnerable areas. The problem could be solved simply by storing all the wastes onboard until visiting the next harbour. Shipping is also a major reason for the introduction of invasive alien species, largely when the tanks with ballast water are emptied. Filtration of water entering or leaving the tanks could suffice to prevent the introduction.

Ships also affect the coasts: the waves generated will erode coastal areas, and the sediments of shallow shipping routes will be affected. Little can be done to avoid this except to site-planning of the harbour. Since most of the harbours have established sites, their location cannot really be affected. Finally, shipping generates noise. In the aquatic environment noise travels much longer than in air, and may disturb the communication of fish and marine mammals. Again, little can be done to reduce noise as long as present type motors are the norm – sailing ships would be much quieter.

In conclusion, many of the environmental effects of shipping could be solved with modest expenses. In this, as in many other cases, applying environment-friendly solutions is more a question of will than of not being able to. One point about goods transport is that we should reduce it by changing to production nearby instead of production thousands of kilometers away to be environmentally friendly.

Kommentoi kirjoitusta. Avainsanat: antifouling paints, oil pollution, invasive alien species, waste management