Sea level rise

When astronauts from Apollo 8 took their first colour photographs of the Earth in 1968, the whole world could see that, in addition to being round, our planet is an intense blue. Half a century later, we know that tides and oceans cover 71% of the land's surface, which lends our world its characteristic tone that transforms it into a unique spot in our galaxy, and maybe even the universe as a whole.

However, as the oceans expand due to rising temperatures, and glaciers and ice sheets melt, the risk of flooding, coastal erosion and the loss of inhabited land increases, threatening infrastructure, local economies, ecosystems and the safety of millions of people around the world. 

Sea level rise could affect cities around the world in very different ways, from Cádiz and Liverpool to Amsterdam, New York, Cancún and Rio de Janeiro. In some cases, rising waters could submerge up to 92% of their land area and reach low-lying urban districts, putting homes, infrastructure and tourist attractions at risk. 

However, this phenomenon does not affect every part of the world equally. Variations in the Earth's gravitational field, caused by differences in the planet's density, mean that sea level is not uniform across the globe. Ocean currents and prevailing winds also redistribute seawater unevenly, while regional differences in water temperature further influence local sea levels. 

To help monitor this phenomenon, NASA provides tools such as the Sea Level Explorer, which offers historical, current and projected sea level data for coastal regions around the world, enabling countries to develop strategies to prevent and mitigate its impacts. 

  SEE INFOGRAPHIC: How will sea level rise affect these cities? [PDF]

Why does melting occur?

The main cause of melting polar ice caps and glaciers is global warming driven by increasing concentrations of greenhouse gases in the atmosphere. These emissions raise the Earth's average temperature and accelerate the loss of both land-based and sea ice. Other factors also contribute, including depletion of the ozone layer, which can intensify climate-related effects in polar regions, particularly Antarctica.  

This climate instability increases the risk of natural disasters associated with changes in temperature and precipitation, leading to more frequent floods, droughts, heatwaves and cold spells as the effects of global warming intensify.  

Consequences of sea level rise

Sea level rise varies depending on the region of the world, posing the most severe threat to inhabitants of islands and coastal areas. Some 745 million people will live through the coming decades exposed to floods, storm surges and other severe events that will prove to be increasingly frequent and devastating to human life and the environment, as the IPCC warned in late 2019 in a special report on oceans and cryosphere.

More recent research published in Nature magazine suggests that sea levels are rising faster than previously projected, meaning the number of people affected could be even higher than earlier estimates. 

Sea level rise can also aggravate coastal erosion, worsen the quality of drinking and irrigation water, damage historical and artistic heritage, affect transport and economic activity in cities, and submerge farmland, natural landscapes, housing and even entire populations, turning its inhabitants into climate refugees.

Predicted sea level rise

Even the most optimistic do not deny the irreversible damage of sea level rise, such as the disappearance of numerous glaciers and a large part of the Arctic surface. The IPCC and other forecasts made to date predict the best case scenario to be a sea level rise of 20 to 30 cm by 2050, and 43 to 50 cm by 2100, as long as CO₂ emissions drop and the Earth's land temperature stays at no more than 2 ºC more than the temperature of the late nineteenth century, as intended by the Paris Accords.

However, if attempts to contain global warming fail and the dreaded mass melting of Antarctica actually takes place, the predictions for 2100 place sea level rise between 84 cm and over 2 metres in the worst case scenarios, according to a study by the NGO, Climate Central, published at the end of 2019 by the journal, Nature. Sea levels could continue rising throughout the following century, reaching as much as 15 metres by 2300.

Iberdrola's commitment to mitigating the effects of climate change 

According to a 2020 report by the Intergovernmental Panel on Climate Change (IPCC), the most effective way to limit changes in the oceans and cryosphere is to implement climate change mitigation strategies. That is why the Iberdrola Group has made electrification and decarbonisation central pillars of its strategy. These processes are essential to reducing greenhouse gas emissions and achieving carbon neutrality. 

One of the key initiatives supporting this commitment is our Biodiversity Plan 2030, which follows a conservation-based approach centred on avoiding, reducing, restoring and offsetting impacts. Through this plan, we aim to avoid developing projects in areas of high ecological value, reduce pollution and restore affected habitats. 

For example, at offshore wind projects such as Vineyard Wind 1, surveys have been carried out to map the extent of the seagrass beds surrounding Cape Poge before and after installation of the export cable, helping to avoid damage to these natural coastal barriers, which play an important role in protecting against sea level rise. 

These initiatives contribute to building a better future and a cleaner, more sustainable energy model – part of a long-standing commitment that has made us a leader in electricity networks and renewable energy.