[Coral-List] Coral on the Great Barrier Reef was 'cooked' during 2016 marine heatwave. REALLY? REALLY? REALLY?

Tue May 8 10:29:12 EDT 2018

For those following this thread, I’m afraid there seems to be some
misapplication of our Coral Reef Watch products in these posts. The
document cited below in ResearchGate uses our Four-Month Bleaching Outlook
to compare the heat stress in 2009 with that seen in 2016:

On Apr 20, 2018, at 12:12 AM, Scott Wooldridge <swooldri23 at gmail.com> wrote:

.... Would it also surprise people to know that the same far northern reefs
experienced heating levels in excess of 8-10 degree heat weeks stress
(highest level on NOAA 4-level scale) in the austral summer of 2008/09, yet
NO bleaching was recorded despite extensive regional searches from
dedicated cruises?

See here for a comparison of the heating stress in 2008/09 and 2015/16.

https://www.researchgate.net/publication/324644910_
Comparison_of_heat_stress_in_the_northern_GBR_for_201516_and_200809

I remember in great detail the 2008/09 situation because I helped plan
cruise trips to search for coral bleaching based on the NOAA heat stress
maps. We fully expected to observe severe bleaching, as evidenced by the
media reporting of the day. But we found nothing (zero bleaching)

Those products in Figures A and B of the document on ResearchGate are not
maps of satellite-observed heat stress. They are the climate model-based
Four Month Outlooks of potential heat stress. In fact, Fig. A in that
document is totally mislabeled as "Heat stress in the northern GBR for
2015/16 bleaching event”. Instead, it is the global map of the 60%
probability outlook of heat stress for March to June of 2016 run on March
15 2016. In short, it is a map of the likely global heat stress in the
month _after_ the heat stress had peaked in 2016.

The actual image for the maximum heat stress alert levels during the 2016
marine heatwave would be found at:
https://coralreefwatch.noaa.gov/data/5km/v3.1/image/
composite/annual/gif/2016/coraltemp5km_baa_max_2016_australia_gbr.gif

In it you can see the reefs of the Far Northern GBR were under Alert Level
2 conditions. In fact, using the Degree Heating Weeks figure found at:
https://coralreefwatch.noaa.gov/data/5km/v3.1/image/
composite/annual/gif/2016/coraltemp5km_dhw_max_2016_australia_gbr.gif

you can see most of the reefs passed 10°C-weeks of heat stress.

In contrast, the maps for 2009 show that the maximum alert level for those
reefs was between a Bleaching Warning and Alert Level 2:

https://coralreefwatch.noaa.gov/data/5km/v3.1/image/
composite/annual/gif/2009/coraltemp5km_baa_max_2009_australia_gbr.gif

and at DHW values of 3-4 °C weeks:
https://coralreefwatch.noaa.gov/data/5km/v3.1/image/
composite/annual/gif/2009/coraltemp5km_baa_max_2009_australia_gbr.gif

An important distinction in the pattern of heat stress in those two years
is that not only was heat stress much higher in 2016 but the high levels of
heat stress clearly penetrated inside the main reef line, whereas in 2009
it stopped at the reef line.

While there is great value to using the climate model-based Four-Month
Bleaching Outlook to understand what heat stress _may_ be seen in the
future, it is only a probabilistic forecast product and does not record
actual values. The satellite-based observation products must be used to
understand that stress actually experienced by corals.

Cheers,
Mark

------------------------------------------------------------------
C. Mark Eakin, Ph.D.
Coordinator, NOAA Coral Reef Watch
National Oceanic and Atmospheric Administration
Center for Satellite Applications and Research
Satellite Oceanography & Climate Division
e-mail: mark.eakin at noaa.gov
url: coralreefwatch.noaa.gov
Twitter: @CoralReefWatch FB: Coral Reef Watch

NOAA Center for Weather and Climate Prediction (NCWCP)
5830 University Research Ct., E/RA32
College Park, MD 20740
Office: (301) 683-3320     Fax: (301) 683-3301
Mobile: (301) 502-8608    SOCD Office: (301) 683-3300

“My hope is that Congress will, at long last, acknowledge that climate
change is real, that humans are contributing to it, and that the potential
consequences of inaction are far greater than the projected costs of
action."
Christine Todd Whitman, EPA Administrator under President George W. Bush,
June 18 2014

On Fri, Apr 20, 2018 at 12:12 AM, Scott Wooldridge <swooldri23 at gmail.com>
wrote:

> Dear Coral Listers,
>
>
> I draw your attention to a press release/article describing the findings
> from the recent Hughes et al. (2018) Nature paper describing the Great
> Barrier Reef (GBR) coral bleaching event in the austral summer of 2015/16..
>
>
> http://www.abc.net.au/news/2018-04-19/marine-heatwave-so-
> bad-it-cooked-parts-of-great-barrier-reef/9667518
>
>
> Now I am all for making the public aware of the dire situation coral reefs
> face during the Antropocene. And maybe such reporting of the results is
> good enough for the general public. But it is certainly NOT good enough for
> scientists, coral reef managers or policy makers.
>
>
> Indeed, it is my personal opinion that the entire reporting of the 2015/16
> coral bleaching event in the previously pristine far northern GBR has been
> rather misleading - with a single-minded preoccupation with sensationalism
> and media grab bites rather than the pursuit of science that increases our
> ability to help save coral reefs into the future.
>
>
> Lets consider the facts for the 2015/16 coral bleaching event, wherein the
> corals supposedly 'cooked' like crabs in a boiling pot of water. Would it
> surprise people to know that the corals SEVERELY bleached at surface
> heating levels less than 3-4 degree heating weeks. Such low heating levels
> usually only warrant a precautionary warning from NOAA (i.e. level 1 on a 4
> level scale) Would it also surprise people to know that the same far
> northern reefs experienced heating levels in excess of 8-10 degree heat
> weeks stress (highest level on NOAA 4-level scale) in the austral summer of
> 2008/09, yet NO bleaching was recorded despite extensive regional searches
> from dedicated cruises?
>
>
> See here for a comparison of the heating stress in 2008/09 and 2015/16.
>
>
> https://www.researchgate.net/publication/324644910_
> Comparison_of_heat_stress_in_the_northern_GBR_for_201516_and_200809
>
>
>
> I remember in great detail the 2008/09 situation because I helped plan
> cruise
> trips to search for coral bleaching based on the NOAA heat stress maps. We
> fully expected to observe severe bleaching, as evidenced by the media
> reporting of the day. But we found nothing (zero bleaching)
>
>
> Claims that the corals 'cooked' in 2015/16 are quite simply absurd and show
> a complete lack of understanding of the eitology of natural coral
> bleaching. Rather than a preoccupation with sensationalism and media grab
> bites, the key question driving the data analysis of the 2015/16 bleaching
> event should be, 'why such high bleaching sensitivity at low thermal
> stress?' or reposed differently 'why such low sensitivity to high thermal
> stress in 2008/09?' And overarching all this, 'what does this mean for
> managing the GBR?', i.e. what can we learn from these 2-events that helps
> provide managers with new levers to increase the 'resistance' of corals to
> warming sea temperatures.
>
>
> In my next post, I will offer some personal insight into the above
> questions.
>
>
> These are important times for coral reef research. We need to recommit to
> good science. We need to ignore sensationalism at all costs. Corals did not
> 'cook' on the far northern GBR in 2015/16. In fact they severely bleached
> at temperatures which are not normally associated with mass bleaching
> events. This is significant and should be clear and evident to all. Indeed,
> this fact holds the key to the survival (or not) of coral reefs into the
> future.
>
>
> Scott
>
>
> https://www.researchgate.net/profile/Scott_Wooldridge
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>

-- 

C. Mark Eakin, Ph.D.
Coordinator, NOAA Coral Reef Watch
National Oceanic and Atmospheric Administration
Center for Satellite Applications and Research
Satellite Oceanography & Climate Division
e-mail: mark.eakin at noaa.gov
URL: coralreefwatch.noaa.gov
Twitter: @CoralReefWatch <https://twitter.com/coralreefwatch> FB: Coral
Reef Watch <https://www.facebook.com/coralreefwatch/>

NOAA Center for Weather and Climate Prediction (NCWCP)
5830 University Research Ct., E/RA32
College Park, MD 20740
Office: (301) 683-3320     Fax: (301) 683-3301
Mobile: (301) 502-8608    SOCD Office: (301) 683-3300

"A world without coral reefs is unimaginable."
Dr. Jane Lubchenco, March 25 2010