The Intergovernmental Panel on Climate Change released their newest Special Report focusing on the reciprocal effects between climate change and the development of the world’s maritime system as well as the cryosphere. The report describes a number of tremendous impacts that may change the world forever and harm billions of people if action isn’t taken to prevent the worst consequences.

The report explains that global oceans are an important regulative system for the global climate. They have warmed unabated since the 1970s and have taken up more than 90% of the excess heat in the climate system. As the report highlights, the oceans have also absorbed around 20-30% of total anthropogenic CO2 emissions since the 1980s. Though this has removed a lot of carbon from the atmosphere, the maritime system has experienced increased and widespread acidification as a result. The report points out that this results in the degradation of this habitat for wildlife, consequently affecting food security for communities all around the world, who depend on healthy fish populations for their subsistence.

 

Predicting different scenarios

More than 100 scientists from all around the world have contributed to the report using a best-case Paris Agreement scenario as well as a business as usual scenario to describe possible impacts of warming oceans and thawing permafrost areas – with dramatic consequences. Of particular concern is the report’s prediction that extreme sea level events, previously considered rare, will become a common occurrence in many locations by 2050, regardless of our climate action. Projections expect these events to change from occurring once per century, to once every year.

Cryospheric impacts inland

Another large focus on the report, is high mountain areas, which are home to almost 10% of the global population. Most types of natural hazards in these areas are projected to change in frequency, magnitude and areas affected as the cryosphere continues to shrink. Floods resulting from glacier lake outbursts or rain-on-snow, landslides and snow avalanches are expected to increase as well as appear in new locations and during new seasons. These mountain areas, alongside polar regions, have already seen changes in terrestrial and freshwater ecosystems resulting from the appearance of land previously covered by ice, permafrost thaw and changes in snow cover. The report also warns that permafrost thaw is among one of many risks in which changes to the hydrological system causes the release of carbon stores. Permafrost ground holds large amounts of organic carbon – by far superseding the amounts of carbon in the atmosphere. Large-scale loss of permafrost cover therefore has the potential to significantly increase the concentration of atmospheric greenhouse gases and to potentially contribute to a “hothouse earth” effect.

The loss of glaciers and ice sheets in polar and mountainous regions together with the expansion of warming oceans also contributes to the rise of sea levels. The report predicts, it could reach 30 to 60 cm or even 60 to 110 centimeters in 2100, depending on the future increase of greenhouse gas emissions.

 

The relationship between us and our planet

Human interaction with the climate is an ongoing theme throughout the report, which discusses both human-related causes and consequences of changes to oceans and the cryosphere. For instance, the report explains that nearly 50% of all coastal wetlands have been lost over the past 100 years due to a combination of localized human pressures, sea level rise, warming and extreme climate events. Based on this, the IPCC predicts that further loss of coastal wetlands could be as high as 90% by 2100, depending on the action taken against climate change. The report warns that societies are going to be exposed and challenged to adapt to future changes to the ocean and cryosphere, even if global warming is kept well below 2°C. If human impacts on the ocean continue unabated, the resulting effects on the ocean health and services will result in an annual lost to the global economy of $420 billion by 2050 and $1.979 billion by 2100.

According to the IPCC, ocean warming, acidification and deoxygenation, ice sheet and glacier mass loss, and permafrost degradation are expected to be irreversible in the short term. In fact, current response times range from decades to millennia, meaning that the ocean and cryosphere will continue to change long after atmospheric GHG concentrations and radiative forcing are stabilized.

 

Offering solutions

Whilst the report describes probable consequences of climate change on oceans and the cryosphere, it  also provides advice as to how best to act against climate change by making use of the potentials of these systems. One of these is the protection and restoration of vegetated coastal ecosystems, such as mangroves, tidal marshes and seagrass meadows. Not only are these important habitats and natural protection against extreme sea level events, they also have the potential to absorb around 0.5% of all global emissions every year. Furthermore, the report highlights that changes to the ocean and cryosphere will have cross-border consequences and therefore cross-border cooperation is vital to minimize risk to resource security and management. Emphasis is made on the necessity of economic and institutional transformations to create climate-resilient development.