The Great Barrier Reef has experienced extensive coral bleaching over the past two years. Faced with this reality, scientists are proposing a range of options to save the reef.
A recent conference showcased new possibilities for enhancing Reef resilience, including boosting coral abundance and geoengineering techniques that would manipulate local conditions to reduce ocean temperatures.
These geoengineering approaches carry their own risks, and require careful management, even at the research and field testing stages.
Technology is needed to buy the reef time
Climate change is affecting the reef through bleaching events, species redistribution, and ocean acidification. Stabilising environmental conditions “to protect current reef biodiversity” requires that global temperatures stay below 1.2℃. Yet modelling of the global community’s current commitments under the Paris Climate Agreement suggests that global warming between 2.6-3.2℃ will occur by 2100. This would destroy the Great Barrier Reef as we know it.
It is not surprising, then, that scientists are looking to buy the reef some time, while the international community works to stabilise and then reduce global greenhouse gas emissions. The Commonwealth and Queensland governments have announced funding for feasibility projects aimed at manipulating surface water temperatures using three different techniques:
- Creating a reflective surface film that would float on the surface of the water. Made from calcium carbonate (the same mineral as coral), the film would reflect sunlight, thereby lowering water temperatures and ultraviolet radiation exposure.
- Marine cloud brightening to also reflect more sunlight away from the reef. The plan is to spray microscopic salt particles into clouds using customised vessels or modified snow machines. This increases the concentration of droplets in clouds and encourages smaller, more reflective droplets to form.
- Water-mixing units with large, slow moving fans that will draw cool water from 10-30 metres deep and deliver it to surface areas to limit coral heat stress. In 2017 this proposal received A$2.2 million in Commonwealth funding, to test eight water-mixing units over a 1km square area of Moore Reef, off the coast of Cairns.
Engineering the climate of Australia’s most iconic natural system carries obvious risks. Indeed, Australia has a history of well-intended attempts to manage nature that have backfired because the risks were not fully understood.
We must be confident that such technological interventions will protect the reef, not contribute to its destruction. This is a problem because scientific trials are supposed to identify and assess risks, so we won’t fully understand what impacts they have until such trials are undertaken.
Governance necessary for public confidence
Building public confidence that potential risks have been identified and addressed is essential to the long-term success of reef geoengineering proposals. Even feasibility studiescan be derailed if they lack public support.
Originally Published by The Conversation, continue reading here.