May well be multifactorial. People debate the climate change thing, I believe mainly on the basis of efforts to blame it on CO2 emissions and set big government up selling 'carbon credits' and exerting more control over our lives. Thing is, there are other potential contributors. Some natural long-term variation, perhaps. And look at the massive global deforestation that's occurred over the centuries.
For sake of argument, perhaps warm water episodes are doing significant damage periodically. In some places, add on pollution, such as sewage, which can fuel algae overgrowth. Not over-fish and wreck the natural balance of life. Still not enough? Okay, decimate large stretches of mangrove forests that serve as nurseries for juvenile stages of many marine species, to further upset the natural balance.
It becomes multi-factorial, where a stressed system is more vulnerable to additional insults. Like a sick 80 year old elder with emphysema from long-term heavy smoking going in the hospital in a debilitated condition, contracting pneumonia and dying of respiratory failure. Cause of death? Well, you could say pneumonia, but there's more to it.
Richard.
