Archives for April 8, 2007

It was all over ABC news yesterday that Australia’s magnificent Great Barrier Reef is in “real danger of disappearing in 20 years”

The journalist, Elizabeth Jackson, was extrapolating from a new United Nation’s 23-page summary of a report on climate change.

This is the second summary report from the United Nation’s this year with the first summary report released in Paris on the 2nd February (blog post and comment on first report here).

The new summary report doesn’t say the reef will disappear at all, but it does paint a bleak picture. There only appears to be one reference to the Great Barrier Reef and the text reads:

“Significant loss of biodiversity is projected to occur by 2020 in some ecologically-rich sites including the Great Barrier Reef and Queensland Wet Tropics. Other sites at risk include Kakadu wetlands, south-west Australia, sub-Antarctic islands and the alpine areas of both countries.”

There is also comment more generally about reefs including:

“Increases in sea surface temperature of about 1 to 3°C are projected to result in more frequent coral bleaching events and widespread mortality, unless there is thermal adaptation or acclimatisation by corals. [emphasis added]

“Mangroves and coral reefs are projected to be further degraded, with additional consequences for fisheries and tourism.

“For example, current stresses on some coral reefs include marine pollution and chemical runoff from agriculture as well as increases in water temperature and ocean acidification.

“As a consequence of intense tropical cyclone activity: damage to coral reefs.” [end of quotes]

I’m still not convinced destructive fishing practices and pollution aren’t a greater risk to the world’s reefs than climate change as detailed in my controversial opinion piece written for The Australian some months ago.

The new summary sets out all the key policy-relevant findings of the Fourth Assessment of Working Group II of the Intergovernmental Panel on Climate Change (IPCC).

The Assessment is of, “current scientific understanding of impacts of climate change on natural, managed and human systems, the capacity of these systems to adapt and their vulnerability. It builds upon past IPCC assessments and incorporates new knowledge gained since the Third Assessment”.

While much of the report is about what ‘could’ happen to the environment given global warming. It is interesting to note what is included in the section on current knowledge about observed impacts of climate change on the natural environment:

“With regard to changes in snow, ice and frozen ground (including permafrost), there is high confidence that natural systems are affected. Examples are:
• enlargement and increased numbers of glacial lakes;
• increasing ground instability in permafrost regions, and rock avalanches in mountain regions;
• changes in some Arctic and Antarctic ecosystems, including those in sea-ice biomes, and also
predators high in the food chain.

Based on growing evidence, there is high confidence that the following types of hydrological systems are being affected around the world:
• increased run-off and earlier spring peak discharge in many glacier- and snow-fed rivers;
• warming of lakes and rivers in many regions, with effects on thermal structure and water quality.

There is very high confidence, based on more evidence from a wider range of species, that recent warming is strongly affecting terrestrial biological systems, including such changes as:
• earlier timing of spring events, such as leaf-unfolding, bird migration and egg-laying;
• poleward and upward shifts in ranges in plant and animal species.

Based on satellite observations since the early 1980s, there is high confidence that there has been a trend in many regions towards earlier ‘greening’5 of vegetation in the spring linked to longer thermal growing seasons due to recent warming.

There is high confidence, based on substantial new evidence, that observed changes in marine and freshwater biological systems are associated with rising water temperatures, as well as related changes in ice cover, salinity, oxygen levels and circulation.

These include:
• shifts in ranges and changes in algal, plankton and fish abundance in high-latitude ocean;
• increases in algal and zooplankton abundance in high-latitude and high-altitude lakes;
• range changes and earlier migrations of fish in rivers.

The uptake of anthropogenic carbon since 1750 has led to the ocean becoming more acidic with an average decrease in pH of 0.1 units [IPCC Working Group I Fourth Assessment]. However, the effects of observed ocean acidification on the marine biosphere are as yet undocumented.” [end of quote]

There is no specific reference to coral reefs in the “observed impacts” section. The comment that there is no evidence of ocean acidification affecting the marine biosphere presumably includes no impact on coral reefs.

In summary the report, like most climate change reports from the United Nations, includes relatively unspectacular observed impacts, is big on all the bad things that could happen, and the Australian media blow this out of all proportion, this time including comment that the Great Barrier Reef could disappear in 20 years.