Predicted effects of global warming on our local ecosystem (by the year 2100):

Water temperature: Logically, as the earth gets warmer, oceans are expected to heat up. This heating isn’t true in all cases –changes in currents and weather patterns are actually expected to lead to cooling in northwest Europe, however climate models predict approximately a 4.5°C increase in surface temperature, which consequentially also leads to an increase in water temperature.

Sea levels: Another common connection with global warming is the rise in sea levels. Contrary to popular belief, this is not caused by melting ice caps, instead by the expansion of the upper layer of the ocean as it heats, and melting alpine glaciers. Sea level rise caused by the melting ice caps is actually balanced out by increased snowfall in these regions. The expected rise is approximately 50cm; however models vary from 15-95cm. Furthermore, local tidal patterns can cause a much greater or lower rise in sea levels. Regardless, it can be expected that Pedder Bay will see a significant rise in sea levels if global warming continues.

Precipitation: Global warming causes an overall increase in precipitation, however the changing weather patterns produce almost unpredictable results across the globe. Recent maps place Victoria and Pedder Bay between an area of 60% increase in rainfall below us and a are of drought (30% decrease in rainfall) above us. While we could fit into either one of these patterns, recent data from RaceRocks seems to suggest rainfall is falling in the region.

Acidification: The final effect of global warming I will comment on here is ocean acidification. The ocean acts like a gigantic carbon sink, absorbing CO2 from the atmosphere. Increased amounts of CO2 increase the oceans absorption. While this limits the effect of greenhouse gasses, once in the ocean the CO2 converts to Carbonic Acid (H2CO3). This increases the overall acidity on the ocean, including Pedder bay, and has a hugely detrimental effect on sea life.

Sources:
Earth's Future Climate
Author(s): Mark A. Saunders
Source: Philosophical Transactions: Mathematical, Physical and Engineering Sciences, Vol. 357, No. 1763, Science into the Next Millennium: Young Scientists Give Their Visions of the Future. Part 1: Astronomy and Earth Sciences (Dec. 15, 1999), pp. 3459-3480
Published by: The Royal Society
Stable URL: http://www.jstor.org/stable/1353858

The Next Ocean: Humanity's Extra CO₂ Could Brew a New Kind of Sea
Author(s): Susan Milius
Source: Science News, Vol. 173, No. 11 (Mar. 15, 2008), pp. 170-172
Published by: Society for Science & the Public
Stable URL: http://www.jstor.org/stable/20465314