[Coral-List] Evidence that ocean warming has caused most Caribbean coral loss

[Ulf Erlingsson]

Doug, 

The hypothesis of those who warn of climate change seems to be that the anthropogenic temperature changes at the present time are more dramatic than anything in the past, and that they will lead to consequences that are unique. They seem to think that past changes were never that dramatic. That is where I beg to differ. In what we Earth Scientists call "Recent" time, as late as a few hundred human generations ago, there were much larger and at least as dramatic changes according to the geological archive. And if we look at absolute temperatures, then it is disingenuous to compare to the 19th or 20th century as a baseline, since that was the peak of the Little Ice Age.

Furthermore, after the existence of an Ice Age covering northern Europe (Germany, Poland, Holland) had been convincingly shown by Swedish geologist Otto Torell in the 1860's, and it later was understood that there had been several, combined with the evidence of falling temperatures, science started worrying about a new ice age. It was in that atmosphere (no pun intended) that Swedish physicist Svante Arrhenius in 1896 calculated that our emissions of greenhouse gases might actually prevent a new Ice Age.

However, we still don't know for sure why the Ice Age happens, although I have an idea which I have presented as a project on ResearchGate, which has to do with ocean circulation, and if that is true, it is very unlikely that global warming can do more than delay the onset a little. 

But back to corals: I am convinced that the biggest issue is NOT global warming, but POLLUTION. 

Ulf 


> On 2017-04-27, at 20:13 , Douglas Fenner <douglasfennertassi at gmail.com> wrote:
> 
> Ulf,
>     It may be that geologists, because of their understanding of the vast expanse of earth history, which has included periods of larger temperature variation than the last few decades, and which some groups of organisms survived, have been more resistant to the evidence of human-caused global warming in recent decades.  However, my understanding is that most if not all geological societies now agree that the recent rapid warming of the earth is mostly caused by humans, by greenhouse gas emissions, deforestation, carbon soot on snow absorbing heat, positive feedback from melting of Arctic ice which reflects light more than water, etc.  In fact, some of the effects of humans, such as the emissions of aerosols (such as SO2 from burning fossil fuels) actually work to reduce global temperatures, though the effects of other emissions are greater and cause net global warming.
>      Am I wrong about the geological societies?
>     Cheers,  Doug

also responding to this:

> Ulf,
>     My understanding is that climate science data supports the view that the rapid increases in world temperature in recent decades has been caused mostly by human emissions, while earlier, more gradual temperature increases were caused mostly by natural processes (in spite of claims that we are in the beginning of a new ice age).  Both of these were present in the graph John presented in his essay.  However, it seems unlikely to me that corals either understand the causes of temperature increases, or care what those causes are.  Corals are impacted by temperature increases, whatever the causes of those temperatures are, surely.  That includes turning up the heat in aquaria in experiments.  So it seems to me that John's graph of increasing temperatures IS relevant to the question of whether corals in the Caribbean have been impacted by temperature increases or not, and I don't see the relevance of the question of what caused the temperature increases, at least to the question of impacts on corals.  The effect of increasing temperatures on corals is a mechanistic thing, higher temperatures stress or kill corals.  Cause of temperature increase is irrelevant for that.
>      That said, it is good to remind us of the broader processes over geological time.  That could include the fact that present temperature increases exceed those that have happened in a very long period of time, well beyond the range of time you've referred to.  
> Cheers,  Doug
>