Ecosystem services provided by the Baltic Sea ... - Naturvårdsverket

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SWEDISH ENVIRONMENTAL PROTECTION AGENCY Report 5873 • Ecosystem services provided by the Baltic Sea and Skagerrak Economic Marine Information groups of marine life as shall be discussed below. The acidification of our seas will continue despite current action (or non-action for that matter). There are no rapid rewind buttons for running down CO 2 stocks. People living at the start of the 22nd century will live with the consequences of our emissions, just as we are living with the consequences of emissions since the industrial revolution. These time-lags are an important feature of climate change inertia. Even stringent mitigation measures will not affect average temperatures changes until the mid-2030s - nor will temperatures peak until 2050. So far a mean 30 % increase in acidity has been recorded, corresponding to a pH decline from 8.16 to 8.05 (99). By the year 2100 pH is believed to have been reduced by 0.2 - 0.4 units. Following alarming news about the lowering of sea water pH from other parts of the world, the Oceanographic Laboratory at the Swedish Meteorological and Hydrological Institute (SMHI) has analysed 14 years of monthly measurements from Swedish seas. The results are no less alarming than in other parts of the world; on the contrary, sea water pH generally shows a continuous and dramatic decline from 1993 - 2007, particularly in the Baltic Sea (100). "The speed and size of the change show that we cannot take for granted the ocean sink for the CO 2 . Perhaps this is partly a natural oscillation or perhaps it is a response to the recent rapid climate warming. In either case we now know that the sink can change quickly and we need to continue to monitor the ocean uptake." Professor A Watson, author of a recent article on CO 2 sequestration (98) Expected consequences of seawater acidification Notwithstanding the paucity of results, there is consensus that seawater acidification affects a number of biological processes like fertilization, larval development and survival (76) Species living on the bottom as well as those depending on calcium carbonate for shells and skeletons are most imperilled (Fig. 9). Especially vulnerable are small marine snails and deep-water corals that live in high latitudes. The colder the water, the more carbonic acid it holds, like the canned soda. In our waters, numerous organisms may become affected, either by direct impact or via resource limitation. A recent Swedish study (101) demonstrated how, due to a complete failure of skeleton formation, no brittle star larvae could survive a 0.2 pH units decrease (the conservative forecast worldwide for the end of this century; Fig. 10). To put this result in perspective, brittle stars constitute an important food source for flatfish, while being important bioturbators. Accordingly, leading scientists predict increased recruitment failure among many other organisms, including commercial fishes, within decades (102). Ecosystem effects might include altered biogeochemical cycling, primary production, food web dynamics, diversity and ecosystem resilience, as well as provisioning services dependent on these processes. 71
SWEDISH ENVIRONMENTAL PROTECTION AGENCY Report 5873 • Ecosystem services provided by the Baltic Sea and Skagerrak Economic Marine Information Figure 9. The larvae of a marine snail. Calcifying organism will face increasing difficulties as marine acidification progresses. © Jon Havenhand Effects of no action The power of large water masses to influence local climate in regard to temperature, wind and humidity will be sustained despite current threats. This applies to the oxygen supply too. As for CO 2 , there are general indications that sequestration in seawater may slow down, while primary production may speed up due to atmospheric change. In any case, it should be clear to everyone, that current levels of green house gas emissions are unsustainable and that the effects of no action will be severe. Not only for the climate and sea surface temperatures, but also for the maintenance of marine chemical composition, supporting the development of a multitude of life forms. How to maintain climate regulation The most sensible way to address climate change and acidification is by reducing CO 2 emissions. Sweden has committed to the environmental goal of halting global warming at 2C. To achieve this goal, the European Council has calculated that Sweden will have to reduce emissions 17 % by 2020. To which extent this result (if achieved) might contribute (or not contribute) to mitigating current acidification remains uncertain. “In state affairs, by foreseeing [problems] at a distance, which is only done by men of talents, the evils which might arise from them are soon cured; but when, from want of foresight, they are suffered to increase to such a height that they are perceptible to everyone, there is no longer any remedy.” Machiavelli 1532 (103) No single threats to the marine environment occur today; rather ecosystems are subjected to a number of constant disturbances. Such chronic stress to marine organisms may be an important factor reducing their adaptability to temperature and pH alteration. Because it will be essentially impossible to halt the development within the next 100 years (or conceivable much longer), mitigation of chronic 72
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Ecosystem services provided by the Baltic Sea ... - Naturvårdsverket

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