Tag: Great Barrier Reef

Scientists at Sea Podcast – Climate Change, why don’t people act? With Catherine Leyshon

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Show Notes

In the last episode we spoke with Paul Butler and Annette Broderick about climate change and how this impacts their work on bivalves and turtles respectively. We also discussed some of the key points of the IPCC’s latest climate change report. If you would like to check that out, click here.

This time, we’re taking a slightly different approach in a chat we had with Professor of Human Geography, Catherine Leyshon. Specifically, we discussed the reasons why, in the face of overwhelming evidence, we appear to do very little in response.

The discussion ranges from why people might struggle to make small, every day changes, right through to governmental/international levels.

“We’re not really set up as a society to reward good behaviour, we tend to sanction bad behaviour”

Why don’t some actions work?

Australia’s Green tax:

The Great Barrier Reef is rapidly disappearing due to climate change.
Photo credit – Toby Hudson

This seemed like a good idea in principle, but ultimately didn’t work out, we’ve collected a few pieces relating to this. You can read about what the taxes were, what impact they had, why they were abandoned, and what has happened as a result:

What was the emissions tax?

“Australia records biggest emissions drop in a decade as carbon tax kicks in”

“Australia abandons disastrous green tax on emissions”

“Australia’s greenhouse gas emissions soar in latest figures”

 

What actions might work?

Mullion Harbour Wall in a storm
Photo credit: Layla Astley

Shifting Shores

In the UK we are seeing some changes. For example, the National Trust have introduced their Shifting Shores project, where they will now be focusing on adapting to changes at their coastal sites, rather than trying to prevent change.

For those of us in Cornwall, Mullion harbour wall is a particularly relevant example, you can read about the challenges the National Trust have faced with this here.

In 2012, Catherine co-authored a paper going into greater depth about this, which you can find here: Shifting Shores: Managing Challenge and Change on the Lizard Peninsula, Cornwall, UK

As Ethan mentioned in the episode, we are seeing some other actions, such as: Dutch parliament to set target of 95 percent CO2 reduction by 2050. There are several other areas covered in the episode, but to find out more you’ll need to give it a listen!

You can also read the IPCC Climate Change Press Release in full here.

Associate Professor Catherine Leyshon:

Catherine is a human geographer whose work combines landscape ecology, social relations and climate change. Catherine’s work on climate change is interesting for many reasons, but one aspect that really makes it stand out is its focus on local communities here in Cornwall. Studies can all too often focus on the distant impacts of climate change, but numerous studies from Catherine help to highlight the potential changes occurring on our door step.

Twitter: @cleyshon 

Link to Scholar list of publications

Hosted by Ethan Wrigglesworth

Episode and show notes produced by Ben Toulson and Ethan Wrigglesworth

#ExeterMarine is an interdisciplinary group of marine related researchers with capabilities across the scientific, medical, engineering, humanities and social science fields. If you are interested in working with our researchers or students, contact Michael Hanley or visit our website!

It’s Stressful Being a Coral! Declining Coral Cover on the Great Barrier Reef

Ben Toulson Leave a comment

Author: Jennifer McWhorter

Jennifer McWhorter is pursuing her PhD in a joint program between the Universities of Exeter and Queensland. Using various climate and ecological modelling techniques, Jen hopes to improve our spatial knowledge of coral reef stressors.

 

The above diagram describes the process of coral bleaching followed by mortality. Source: Great Barrier Reef Marine Park Authority (GBRMPA)

 

Similar to humans experiencing a fever, coral reefs undergo similar stress. The more frequent the fever and the longer the fever lasts, the more life threatening it becomes. Sea surface temperatures in the ocean are increasing at an alarming rate due to human inputs of carbon dioxide into the atmosphere (Ekwurzel et al., 2017). In 2016/2017, the Great Barrier Reef (GBR) experienced two back-to-back severe warming events that caused widespread coral bleaching[1]. According to the Australia Institute of Marine Science, hard coral cover on the GBR has declined at a rate that has never been recorded.

 

Figure 2. “Large-scale spatial patterns in change in coral cover and in heat exposure on the Great Barrier Reef, Australia. A, Change in coral cover between March and November 2016. b, Heat exposure, measured in DHW (in degree C-weeks) in the summer of 2016. Map template is provided by Geoscience Australia (Commonwealth of Australia (Geoscience Australia) 2018).” Source: Hughes, T. P., et al., 2018

 

In addition to coral bleaching, cyclones and crown-of-thorns sea star outbreaks have been the main cause of decline in coral cover on the GBR within the past four years. The northern area of the GBR is expected to have lost about half of its’ coral cover. This estimate reflects the impacts of two episodes of severe coral bleaching from 2014-2017 and two cyclones.  The central reef has experienced a decline in coral cover from 22% in 2016 to 14% in 2018 due to coral bleaching and the ongoing southward spread of the crown-of-thorns sea star. Even though the southern portion of the GBR was not exposed to the 2016/2017 warming events, coral cover has dropped from 33% in 2017 to 25% in 2018. On the southern reefs, the crown-of-thorns sea star outbreaks appear to be the main cause for the most recent decline.

 

During my last trip to Australia, I assisted in injecting vinegar into the crown-of-thorns sea stars at Lodestone Reef on the GBR. The vinegar kills the sea star within 24 hours potentially reducing their threat to hard, or stony corals. Photo Credit: Chris Jones

 

“Clearly the reef is struggling with multiple impacts,” says Prof. Terry Hughes, Director of the ARC Centre of Excellence for Coral Reef Studies. “Without a doubt the most pressing of these is global warming. As temperatures continue to rise the corals will experience more and more of these events: 1°C of warming so far has already caused four events in the past 19 years.”

“Ultimately, we need to cut carbon emissions, and the window to do so is rapidly closing.”

 

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[1] Coral bleaching – Coral bleaching occurs when the relationship between the coral host and zooxanthellae (photosynthetic algae, NOAA), which give coral much of their colour, breaks down. Without the zooxanthellae, the tissue of the coral animal appears transparent and the coral’s bright white skeleton is revealed. Corals begin to starve once they bleach. (GBRMPA)

 

Additional Resources:

Ekwurzel, B., Boneham, J., Dalton, M. W., Heede, R., Mera, R. J., Allen, M. R., & Frumhoff, P. C. (2017). The rise in global atmospheric CO2, surface temperature, and sea level from emissions traced to major carbon producers. Climatic Change, 144(4), 579-590.

Hughes, T.P. & Kerry, J.T. Back-to-back bleaching has now hit two-thirds of the Great Barrier Reef. The Conversation https://theconversation.com/back-to-back-bleaching-has-now-hit-two-thirds-of-the-great-barrier-reef-76092 (2017)

Hughes, T. P., Kerry, J. T., Baird, A. H., Connolly, S. R., Dietzel, A., Eakin, C. M., … & McWilliam, M. J. (2018). Global warming transforms coral reef assemblages. Nature, 556(7702), 492.

Media Release: Two Thirds of the Great Barrier Reef hit by back-to-back mass coral bleaching

Long-term Reef Monitoring Program – Annual Summary Report on coral reef condition for 2017/2018

 

#ExeterMarine is an interdisciplinary group of marine related researchers with capabilities across the scientific, medical, engineering, humanities and social science fields. If you are interested in working with our researchers or students, contact Michael Hanley or visit our website!