Welcome to the fifth of our weekly areas of focus on climate action, providing encouragement and seeking to inspire action within all the 22 Methodist Churches in the Ipswich area.
By the time the COP26 summit begins on 1st November, we will have covered 9 distinct areas of concern.
This week’s focus
This week we are looking at sea and ocean effects, the most damaging of which arise when warmer conditions cause sea level to rise.
Why Does Climate Change Affect the Seas and Oceans?
Climate change is happening because more energy from the sun is trapped by the greenhouse gases, instead of being reflected back into space. Roughly 90% of this additional energy is stored in the oceans because water is much better at absorbing and storing this energy than the land.
We are familiar with the idea that metals and other solid substances usually expand as they warm up. This is also true for water. So, as the planet warms up, the water in the seas and oceans expands. Warming also melts mountain glaciers and sea-ice adding more water into the oceans.
These two effects cause the worldwide sea levels to rise by about 3.6mm each year. The graph shows the result of nearly 30 years’ observation by NASA of the average sea level. Almost 4 inches or 100mm rise in sea level.
Most of the absorbed energy warms up the surface layers of the body of water, whether it is a small lake or a vast ocean. I have a vivid memory of swimming in Lake Powell in Colorado. Firstly, the surprise at just how warm the water was, almost immediately followed by the shock of how cold it was only a foot or so below the surface of this large mass of calm water.
Tidal and wave action plays a large part in stirring up the water surface and spreading the heat deeper into the body of water. These thermal gradients also contribute to the effects of climate change on the seas and oceans. The turbulence of mixing the warm surface waters with the cold waters varies considerably between shallow coastal and deep-sea regions.
Evaporation also increases with water temperature, so changes in surface water temperature directly affects cloud formation. This feeds into the whole water cycle which redistributes water from the seas and oceans into precipitation over land-masses. Changes to sea temperature therefore feed directly into changing patterns of rain and snowfall, as well as more general levels of humidity. Although we frequently think about the way life is affected by higher temperature, changes in humidity can be more devastating to life than extreme temperature alone.
It would be easy to miss the significance of sea and ocean conditions in both humidity and cloud formation. Clouds play a complex, and only partially understood, effect in climate change, which will be covered in next week’s study. Recent research has demonstrated that early models trying to predict the impact of climate change were
The solubility of minerals, salts and nutrients are sensitive to temperature, affecting the overall acidity and relative concentration of ingredients within what may be highly localised conditions. Shallow, stagnant waters will be affected most by the combination of warming and evaporation. At one extreme, these conditions can create extreme concentration of minerals in salt flats with loss of marine environment. In shallow tidal conditions, the effects of temperature are less dramatic but still have a larger impact on conditions than in deep-sea areas. The impact of climate change on sea and ocean environments is often highly localised because of the interplay between all these variables.
The lowest order of marine life such as algae and single celled micro-organisms are highly sensitive to these local conditions, with inevitable consequences to life throughout the whole marine ecosystem, as described in our focus on loss of ecosystems.
What Impact do these Changes Have?
The rise in sea level has an obvious impact on low lying coastal areas, but it can be hard to understand how such a small rise in sea level can have a big impact.
In shallow coastal waters, the steeper thermal gradients, warmer waters and tidal effects combine to amplify the impact of rise in sea level, so that sea defences are more likely to be breached especially at the highest spring tides, or in storm surges.
Many of the small pacific islands and atolls are especially vulnerable, because of their isolation and the natural reef defences on which they rely. Many of these countries are already suffering the consequences of rising sea-levels. They have been forced to adapt to the levels of climate change that has already happened, and they face even more devastation as the temperatures and sea levels rise still further.
One of the videos from the Methodist Climate Justice For Action (CJ4A) campaign tells how climate change is a lived reality for the people of Fiji. It tells how a whole coastal community faced with encroaching sea had to face the disruption and challenge of relocating with all that meant to the established livelihoods and relationships.
As we see time and again, the biggest impact of climate change falls on poorer and more vulnerable communities. On a global basis, many indigenous communities live with a respect and understanding of the delicate balance of nature, yet., like the people of Fiji, they can be hardest hit, and it can be too easy for industrial nations to avoid taking responsibility, when the impact is being felt so far away. Hear another story from church leaders in Fiji.
In East Anglia, the threats of sea level rises are too close to be ignored. Conditions in the North Sea create a particularly potent mix of sea-water surges from a combination of strong tidal fluctuation and storm conditions. Coastal erosion and new cliff falls on the Norfolk Coast feature regularly on local news. Coastal floods especially at the spring tides are a frequent reminder of the risks.
In the map of East Anglia, shown here, the areas highlighted in pink shows the forecasted reach of severe flooding in 2040. On the current trajectory. London, the Broads, most of the coastal strip in Suffolk, the city of Cambridge and most of Lincolnshire are under threat from the additional 60-70mm predicted average rise in sea level.
The map shown here is a snapshot taken from Climate central’s interactive mapping tool. This allows users to explore how the threat changes throughout the century. It is available here.
The low lying polders in the Netherlands are large areas artificially reclaimed from the sea, so are especially vulnerable. Rotterdam is Europe’s busiest part handling more goods than any other port. The map shows how vulnerable European trade routes are to the worst effects of sea level changes.
Some of the threat from rising sea level is less visible. Depending on the local soil and rock substructure higher sea levels may manifest through changes to the water table, posing a threat to structural stability of buildings, and disrupting utility services and drainage.
Some of the threat from rising sea level is less visible. Depending on the local soil and rock substructure higher sea levels may manifest through changes to the water table, posing a threat to structural stability of buildings, and disrupting utility services and drainage.
Miami is already facing these effects with surface drainage overflowing. Damage that led to the collapse of a 12 storey building in June 2021 can probably be attributed to climate change.
Wetland and marginal land areas are especially vulnerable as changes in sea level threaten the boundary between salt and fresh water. Wetlands are important because they are amongst the most diverse habitats. Coastal areas are also subject to more erosion The planting of mangroves is increasingly being recognised as an important way to stabilise the boundary between land and sea. Like other forested areas, mangroves are also effective at sequestering carbon dioxide, to reduce the total volume of greenhouse gases.
Human Impact
- A study in 2019 raised the estimate of people at risk from coastal flooding from 100m to 300m, and by 2021, this number had risen again to 410m.
- Current prediction indicate that the sea level will have risen between one and 6 feet above current levels, but this figure will depend on how successful we are at reaching net zero and slowing, halting or even reversing climate change.Floods are the dominant natural disaster causing death and destruction in the USA.
- As the polar ice melts, sea level will rise at a faster rate, and the temperature rise will accelerate loss of land glaciers, with downstream flooding, greater land erosion pouring more water into the sea.
- Wetlands are under increasing threat of being lost both by the shifting of salt and fresh water boundaries, and by farmers seeking to expand agricultural land use.
What Can We Do?
- understand and reduce your carbon footprint is the single most important thing to do, to avoid the worst effects of rising sea levels;
- buy more local goods and produce, to reduce the energy used in transporting goods long distances when they could be sourced locally;
- lobby your MP to ensure that financial aid and support is maintained to the small island nations;
- if you live on or near coast that is threatened, plant shrubs and grasses that will be resistant to hotter, saltier, windier conditions whilst helping reduce erosion;
- seek out and give to a charity specialising in planting to protect coastal areas – e.g. the Global Mangrove Trust or the Worldview International Foundation
Learn More
- NASA report on measuring the energy stored globally in seawater
- NASA video on rising sea levels
- News item from Climate.Gov explaining the link between sea level and climate change
- Report from Climate Central on the worsening of the threat from rising sea levels
- Intergovernmental Partnership on Climate Change (IPCC) report on threat to low lying island communities
- International Institute for Sustainable Development report on climate threat to Small Island Developing States
- Carbon Brief organisation report on loss of polar sea ice
- NASA video on loss of sea ice
- National Geographic focus on rising sea levels
- World forest organisation report on the importance of mangroves
- World Wildlife report on the importance of wetlands
- Report from Harvard Kennedy business school on sea level effects on Miami
World Environment Day Exemplar
On 5th June 1974, the first World Environment Day was marked. Every year since then, a host city has brought focus to an environmental topic that was particularly pertinent to them.
In 2014, Bridgetown Barbados was chosen as the host city, with the theme Raise Your Voice, not the Sea Level. As an island nation, Barbados and other Caribbean Countries face the same challenges that Fiji and the Pacific islands do. Sixty of these small island nations work together under the banner Small Island Developing States (SIDS) and are recognised by the UN as an important group with a small population, but facing some of the worst aspects of the climate crisis. Barbados was chosen to represent this group as the 2014 World Environment Day host. Read more here.
This Week’s Prayer
Pray for those who live in areas threatened by loss of homes and livelihoods as sea levels rise, storms rage and fertile land is lost.
Watch this powerful video prayer for the ocean from the Archbishop of Polynesia.
Key Messages
- global warming will lead to rises in sea level as water expands and ice melts;
- many atolls, low lying areas and several pacific islands will become uninhabitable;
- coastal cities will be liable to flooding;
- port infrastructure will be lost with severe impact on global trade;
- warmer tropical seas will create more violent storms, more frequent and faster moving hurricanes and typhoons;
- more violent storms and higher sea levels will increase rate of coastal erosion;
- mangroves and wetland areas are important to stabilise coastal areas and secure habitats facing sea level rise.