World Resources Institute- Reefs Revisited

This second blog post will focus on the World Resources Institute Reefs Revisited report. This was published by the WRI in 2011, and was a follow up to the original report published in 1998. It was published to raise awareness of the threats posed to coral reefs and also outlined methods to help combat the threats that are faced by corals.

Reefs revisited is going back to the worlds coral reefs to see whether they are still in danger, and if they are, what can be done to combat this change.

The study found that there are 800 types of coral around the world, so diversity is still at good levels. However since the original report was published, there have been vast increases in population. This has led to an increase in industrialization, agricultural development, commerce and greenhouse gas emissions. This all has an effect on global temperature, which then affects coral reefs. The ocean temperatures and ocean acidity is now the highest they have been for 400,000 years. The higher temperatures will result in bleaching. Bleaching is when the higher temperatures forces the symbiotic algae to leave the coral reefs, and so they will be ‘bleached’ as the algae is the component of coral’s colour. The loss of this bacteria makes it very difficult for the coral to feed as they can no longer use photosynthesis. It will force the coral into an almost torpid state. It is possible for them to come out of this bleached state, however in order for this to happen ocean temperature must decrease.

FIGURE 1

From Figure 1, we can see that the corals have been classified depending on how threatened they are. Blue is low threat, yellow is medium, red is high and purple is very high. Large portions of the Great Barrier Reef is classed as low which is promising as this is the largest coral reef found in the world. Worryingly, large proportions of Indonesia and Thailand reefs are rated as high threat. this could be due to poorly governed tourism in the area.

The study identified threats to coral as being either global or local. Local threats are those that take place in close proximity to the coral, which includes more sewage discharge and watershed based pollution, as well as higher levels of reef erosion. Global threats are threats that effect the coral indirectly, through human impacts on global temperatures and ocean chemistry.

The combination of both local and global threats leaves coral reefs largely under threat. The study found that when thermal stresses are added to the local stresses of the different reefs, 75% will be classed as threatened. This is a troublingly large number. Looking at individual areas, we can see that the most at risk area is Southeast Asia, where 90% of reefs are classed as threatened. These provide a great source of income for countries such as Thailand and the Philippines. Tourism and fishing are massive factors for these economies, and so without the coral reefs there will be widespread unemployment, as many regions are dependent on the coastline and what can be found in the oceans. The story doesn’t get much better as you move to other areas. The Atlantic Ocean’s reefs are threatened at a rate of more than 75%, with over 30% as very high risk. The Pacific Ocean is the least at risk, but still with 50% of its reefs threatened. This is obviously a problem that is not going to get better by itself. Going back to the effect this will have on countries such as the Philippines, we can see the magnitude of the effect of lost coral reefs on coastal communities. 275 million people throughout the world live within 30km of coral reefs. The socio-economic factors associated with loss of coral reefs include:

• Changes in the fish population that surrounds the reefs. Bleaching could lead to fish moving away from the reefs, meaning fishermen then struggle to catch enough fish to make a living.
• There may also be a decrease in the species diversity when corals become bleached, and so the amount of tourism may decrease as the reefs are no longer as attractive as there are less fish. Tourism is a large part of the economy for many of these reef-bearing countries such as Thailand, and a loss in tourism would substantially lower GDP (looking at the Maldives, 96.5% of their GDP is dependent on tourism, so they absolutely cannot afford to lose their coral reefs).
• The reefs also provide a large reserve of pharmaceutical materials, which if bleaching persists will mean a lack of medicine for people locally and globally. Many people in poorer countries will not be able to afford increased prices in medicinal care.

 

So as we have seen then, the report doesn’t look too promising. With so much of the world’s reefs threatened, is there any way of salvaging them? Well there may be, if action is taken promptly, and the action is widespread. The report outlined ways in which coral reefs can be saved. Reducing the amount of co2 emitted into the atmosphere is one way of ensuring the survival of coral reefs. Less co2 will help to reduce temperatures as the greenhouse effect caused by co2 and other particulates will be reduced. There are other methods suggested as well, such as managing coastal development, preventing local threats such as pollution into the ocean from taking place. Action needs to be taken soon, as coral reefs don’t have long before it is too late.


the full report can be downloaded here: http://www.wri.org/publication/reefs-risk-revisited