The ocean is inextricably linked to our climate. Rising air temperatures due to global warming are melting the polar ice caps and dissolving glaciers, leading to rising sea levels. But the ocean is also playing a crucial role in protecting us from the worst effects of climate change. Scientists say the seas have absorbed 90% of all the warming that has taken place in the past 50 years.
- The ocean is a massive carbon sink, protecting us from the worst of climate change.
- But rising air temperatures are melting glaciers, while warming seas are bleaching coral.
- Action like coral reef restoration is already underway – and research has found some corals to be more resistant to higher temperatures.
- And there are now calls to designate Marine Protected Areas for 30% of the ocean by 2030.
On the rise
The Intergovernmental Panel on Climate Change (IPCC) says that by 2100, sea levels will be between 0.26 metre and 0.77 metres higher than today. It’s estimated that by 2100, rising sea levels will threaten 200 million people who live in low-lying coastal areas. Researchers say that almost half of the world’s sandy beaches could disappear as sea levels rise. It’s estimated that by 2050, more than 570 cities will be affected by a sea level rise of 0.5 metres.
The IPCC also estimates that even if the rise in global air temperatures can be held to 1.5°C, sea temperatures will rise by at least 2 °C by the end of the century. Rising sea temperatures are to blame for “coral bleaching”. When the water is too warm the corals expel the algae living in their tissues and turn white. Scientists say that coral can recover from bleaching events but it is permanently weakened.
Our changing waters
Meanwhile, melting freshwater from the world’s polar ice sheets changes the chemical composition of the sea making it hard for some species to survive. A study of the Baltic Sea warned that reducing salinity could threaten zooplankton, the tiny creatures who represent the foundation of the marine food chain.
Freshwater also changes ocean currents and if these fail or change course it can lead to oxygen-depleted “dead zones” where marine animals and plants cannot survive.
The oceans are our biggest carbon sink, absorbing around one-third of the CO2 emitted by human activity since the start of the Industrial Revolution. Adding CO2 to seawater in these quantities acidifies the oceans and this is affecting many marine species, especially clams, mussels and sea snails which are unable to grow their shells in acidified waters.
Coral research is making waves
Conservationists and community groups are taking action to restore their coral reefs. In Jamaica, which lost 85% of its coral to hurricanes and pollution, “coral gardeners” are nurturing young corals. There’s hope, even, for the Great Barrier Reef in Australia, where scientists have developed a process they call “coral IVF” in which they collect coral sperm and eggs and grow new young corals which are then implanted in areas that have been bleached. They say the results are promising.
Meanwhile, corals in the Red Sea have been found to keep their colour, showing resistance to higher temperatures. Scientists conducting a genetic analysis on coral samples in the Gulf of Aqaba found those corals, and the algae and bacteria they live in symbiosis with, can withstand average temperatures 5°C higher than what they typically experience. It means they can identify ‘super coral’ that can withstand heat stress.
The carbon sequestration that the ocean provides will be vital if we are to slow the rate of global warming, says the International Union for Conservation of Nature (IUCN) which has called for 30% of the ocean to be designated as Marine Protected Areas (MPAs) by 2030.
Fishing and tourism needs to become more sustainable and coastal development needs to be controlled to prevent marine environments being harmed, says the IUCN.
This is how climate change is impacting the ocean | World Economic Forum (weforum.org)
Ireland’s Marine Area
Ireland’s marine area is 4 times its land area. Marine Protected Areas are geographically defined maritime areas with certain protections for conservation purposes. The Government aims to designate 30% of our maritime area as MPAs by 2030. Currently our MPA coverage is at 2.13%
The Department of Housing, Local Government and Heritage are currently running a public consultation on expert advisory group report entitled ‘Expanding Ireland’s Marine Protected Area Network’ The report considers:
- what features of our marine environment should be protected
- why they should be protected, and
- how they should be protected.
The public consultation aims to gather the views and perspectives of a wide range of people, in order to guide the Government in this work and underpin the expansion of Ireland’s MPA network. Closing 30th July.
gov.ie – Public Consultation on expert advisory group report entitled “Expanding Ireland’s Marine Protected Area Network” (www.gov.ie)