September 21, 2021

Recent Climate Change News in Perspective

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Extreme weather — floods, drought, hurricanes and cyclones — around the world has been in the news throughout the year. The risk consulting firm Aon has reported that the world has experienced 30 weather-related disasters, each causing more than $1 billion in damages, so far this year. Of course, aquaculture infrastructure is not immune. In one example, Cyclone Tauktae flooded a large expanse of shrimp farms in Gujarat, India. Such instances are expected to become more common in the future.

There were two pieces of concerning climate change news in August. First, a study published in Nature Climate Change reported that there are indications that the Atlantic-Meridional Overturning Current (AMOC) has slowed down by around 15-20 percent in the 20th century, is now as weak as it has been in more than 1000 years and could be approaching a tipping point. The AMOC is part of the thermohaline, “conveyer belt” oceanic circulation system. Warm, relatively higher salinity water moves poleward along the sea surface. As it cools at higher latitudes, the higher density water then sinks and moves towards the equator along the sea floor. Melting of the Greenland ice sheet and increased precipitation and runoff from North America has reduced the density gradient that drives the overturning circulation.

The AMOC is thought to operate in one of two possible stable states: on or off. A weakened or collapsed AMOC has major implications for the climate of northern Europe, where conditions could become much colder. Long-term, this should be alarming news for the sustainability of the regional salmon farming industry as well as for many North Atlantic fisheries. Disruptions to the interconnected system of oceanic circulation also has implications for monsoonal rainfall patterns, upon which the livelihoods and food security of hundreds of million people depend. Such disruptions could also affect the production of crops used as human food and as ingredients in animal feeds, including aquafeeds.

The other piece of recent climate news was the release of an updated report by the IPCC. That report affirmed that the Earth has warmed by 1.1 C since 1850, with a now stronger link established between human activity and climate change. The dire nature of the report led UN Secretary General António Guterres to say that it represents a “code red for humanity.” Although the report acknowledges that certain levels of climate change are all but certain, it also provides grounds for optimism, indicating that there is still time to moderate the worst potential effects of greenhouse gas emissions and that it is still possible to stabilize temperature at around 1.5 C.

Unfortunately, many media stories covering the recent IPCC report have been sensationalistic, painting a bleak picture of our future. Some thoughtful critiques of the recent IPCC report (see Roger Pielke Jr.) have focused on the likelihood of the various scenarios used by the IPCC to assess future conditions. The scenarios that have received the greatest media attention happen to be those that are least likely, those overestimating the per capita use of coal. The extreme scenario that the IPCC viewed as most likely in 2013 is now seen to be much less likely. That’s good news! Climate change denialism does not help advance a climate policy agenda to mitigate future impacts, but neither does climate change alarmism.

Perhaps incited by distortions in media coverage of recent climate change news, there is little doubt that people, especially young people, are feeling anxious, helpless and hopeless, some to the point of despair. This feeling can be paralyzing, especially when pondering dystopian futures of mass migration from coastlines and the breakdown of social order. What can one individual do? It is a seemingly intractible problem because the solutions are seemingly out of reach at such a high level, at the levels of governments that set policies like fuel standards and public transportation subsidies or of the large, global refineries and coal companies that are the major emitters of greenhouse gases. Cynicism only reinforces the status quo.

From 60 to 90 percent of emissions from aquaculture are derived from the use of aquafeeds and there are some exciting efforts underway to improve the environmental performance of feeds. Major feed companies like Cargill, BioMar, Aller Aqua and Skretting are now producing feeds with lower emissions than previously. In part, this is related to substitution of soybeans produced in Brazil with those from other sources. The land-use change associated with soybean farming in Brazil, greatly increases the environmental cost associated with Brazilian soy production. Aquaculture ecolabelling programs such as ASC and BAP now include consideration of greenhouse gas emissions in their feed mill standards.

Studies of emissions from fed aquaculture tend to focus (rightly) on the importance of feed. However, drawing a bigger box around the system to include product form and transportation to market is needed. We need assessments of representative farmed seafood whole value chains. One example of this is indicated in a study of Norwegian seafood products conducted by Nofima that calculated that the CO2 emissions (in kg CO2e/kg edible product) of farmed, whole, frozen salmon sent from Norway to Shanghai, China by ship and road was about 7.1, whereas sending whole, fresh salmon by air and road was about 19.4. Clearly, product form, transportation distance between production area and market center, and choice of transport method is also important in determining environmental footprint.

Despite aquaculture being responsible for only 0.5 percent of total global greenhouse gas emissions, we should not stand by complacently. Change is required at all levels, from individual to global, to move towards bluer foods. As aquaculture professionals, we need to do what is in the capability and power of each of us to make a difference. We need to work collectively on developing technical solutions and improvements and to influence policy. And finally, we need to think long-term about this problem and act with patient urgency.

— John A. Hargreaves, Editor-in-Chief

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About John A. Hargreaves

World Aquaculture - Editor in Chief. Aquaculture expert with 40 years of experience in research, teaching, and development. Freelance consultant on commercial aquaculture and international development projects.

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