Climate change is the most pressing long-term global challenge we face today. It threatens our health, security, economic stability, and our quality of life. As human activity continues to heat up the Earth’s atmosphere, we are releasing massive amounts of greenhouse gases into the air. These pollutants trap solar energy in the atmosphere, raising temperatures on Earth at a rate of about 1.7 degrees Celsius per century since 1970. This affects all aspects of human existence, from communities that live near coastal zones to food production systems around the world.
On World Ocean Day 2022, and as part of the United Nations Ocean Decade, we should reflect on the state of the ocean and what we can do to address the increasing challenges facing the ocean. The ocean is a huge resource for humanity and the planet as a whole. It provides food, water and other resources essential for human existence and the environment. Indeed, more than three billion people rely on the ocean for their livelihoods. And the ocean is also an integral part of the climate system. Oceanographers and climate scientists are working tirelessly to understand the effects of climate change on the ocean and the environment.
Martin Visbeck, ISC Board Member and head of the Physical Oceanography research unit at GEOMAR Helmholtz Centre for Ocean Research, reminds us that “World Ocean Day provides a unique opportunity for the marine community to raise awareness about how the ocean is connected to people.”, but also that the day “reminds us that we only have one globally connected ocean, that is directly linked to our planet’s climate and provides opportunities for sustainable use and protection to safeguard our common future.”
As the Earth’s temperature rises, glaciers and ice sheets are melting. The rise in sea level is happening all over the world, and it’s cumulative – the ocean is rising faster now than it did 100 or 1000 years ago. By the end of this century, the sea level could be about three feet higher than it is now, according to the IPCC’s Special Report on the Ocean and Cryosphere. The areas of the world that are most vulnerable to these impacts are low-lying coastal areas and island nations. With increasing global surface temperatures, the likelihood of droughts and increasingly intense storms is higher. As more water vapour is evaporated into the atmosphere it becomes fuel for more powerful storms to develop. Storms cause more damage to coastal communities, amounting to billions of dollars in losses each year. Taken together, climate change, acidification and sea level rise are affecting the ocean in multiple ways, and all are having an impact on the global climate.
“The ocean is strongly linked to the climate system, it stores and transports large amounts of heat, moderates the regional and global climate but also is directly affected by climate change with ubiquitous warming, rising sea levels, loss of dissolved oxygen and rapidly increasing oceanic heat waves, stressing the ocean’s ecosystem often beyond recovery.”– Martin Visbeck, ISC Board Member and head of the Physical Oceanography research unit at GEOMAR Helmholtz Centre for Ocean Research
Furthermore, as the ocean absorbs more carbon dioxide (CO2), it becomes more acidic. The ocean is a crucial factor in the global carbon cycle, and over time it can have a significant impact on climate. When CO2 enters the ocean, it forms carbonic acid, which negatively affects marine ecosystems and animal populations. Acidification also makes it more difficult for marine plants and animals to create their own shells and skeletons.
There are several ways that humanity can help to prevent or mitigate damage from climate change to the ocean. We can reduce our own emissions, help to protect and restore vital coral reefs, and develop better water management practices. When science teaches us that ocean habitats (seagrasses, salt marshes, mangroves, etc.) can sequester carbon dioxide from the atmosphere at rates up to four times higher than terrestrial forests, we need to consider the ocean as a pillar of climate change mitigation.
Martin Visbeck confirms that “the ocean and its related maritime economy provide opportunities to mitigate climate change by producing CO2-free energy by wind, currents and its vertical thermal gradient. It can absorb and store CO2 from the atmosphere and contribute to the desired reduction of CO2 in the atmosphere. Ocean industries can reduce carbon emissions and other pollutants by modern ship propulsion systems based on low CO2 fuels or electric propulsion.”
In their attempts to mitigate climate change, decision-makers must consider the state of the ocean an indispensable factor. Nonetheless, as pointed out by Visbeck and many other oceanographers and climate scientists worldwide, “all of this requires global cooperation, awareness, knowledge, and action. Together we can imagine a prosperous future for the ocean, climate, and people.”
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Photo by Nick Dunn on Unsplash.