Another “climate sensitivity” to join the long list of global warming exaggerations. A coral reef has recovered from a severe “bleaching” event in just 12 years to a level that was thought to require many decades. In fact the assumption that the cause of the severe disturbance in in 1998 was due to global warming is itself looking very shaky. After all, if it was due to global warming (rather than some local temperature or other event) then why on earth did it reverse in 1998? Or is it just a coincidence that no global warming has been observed since that time?
Polar bear numbers are increasing, clouds may “cool” more than they “heat”, the earth’s green cover is increasing, the Antarctic has more ice than it ever had and the Arctic ice variability is not unprecedented and glaciers are not melting at any greater rate than the pre-industrial rate. It is becoming increasingly clear that the “sensitivity” of the global climate to carbon dioxide has been grossly exaggerated.
Location of Reef building corals (Photo credit: Wikipedia)
“Recovery of an isolated coral reef system following severe disturbance”, by J. P. Gilmour, L. D. Smith, A. J. Heyward, A. H. Baird and M. S. Pratchett published online at Science on Friday, 5th April, 2013.
Abstract: Coral reef recovery from major disturbance is hypothesized to depend on the arrival of propagules from nearby undisturbed reefs. Therefore, reefs isolated by distance or current patterns are thought to be highly vulnerable to catastrophic disturbance. We found that on an isolated reef system in north Western Australia, coral cover increased from 9% to 44% within 12 years of a coral bleaching event, despite a 94% reduction in larval supply for 6 years after the bleaching. The initial increase in coral cover was the result of high rates of growth and survival of remnant colonies, followed by a rapid increase in juvenile recruitment as colonies matured. We show that isolated reefs can recover from major disturbance, and that the benefits of their isolation from chronic anthropogenic pressures can outweigh the costs of limited connectivity.
PhysOrg writes: Scott Reef, a remote coral system in the Indian Ocean, has largely recovered from a catastrophic mass bleaching event in 1998, according to the study published in Science today. The study challenges conventional wisdom that suggested isolated reefs were more vulnerable to disturbance, because they were thought to depend on recolonisation from other reefs. Instead, the scientists found that the isolation of reefs allowed surviving corals to rapidly grow and propagate in the absence of human interference. Australia’s largest oceanic reef system, Scott Reef, is relatively isolated, sitting out in the Indian Ocean some 250 km from the remote coastline of north Western Australia (WA). Prospects for the reef looked gloomy when in 1998 it suffered catastrophic mass bleaching, losing around 80% of its coral cover. The study shows that it took just 12 years to recover. Spanning 15 years, data collected and analysed by the researchers shows how after the 1998 mass bleaching the few remaining corals provided low numbers of recruits (new corals) for Scott Reef. On that basis recovery was projected to take decades, yet within 12 years the cover and diversity of corals had recovered to levels similar to those seen pre-bleaching.
The k2p blog 