Described as a ‘code red’ for humanity, the latest report from the Intergovernmental Panel on Climate Change spells out a stark warning over the future of the planet.
The United Nations report demonstrates unequivocally that climate change is man-made and that some of the impacts, including sea-level rise, are unavoidable. There are a number of ‘possible futures’ and the world’s developed nations have a rapidly closing window of opportunity to radically reduce fossil-fuel emissions and prevent the most severe consequences.
Here we look at five key areas with the most direct influence on Cayman.
1. Rising seas a certainty
Continued sea-level rise is an irreversible consequence of climate change that is “locked-in” for centuries, the report concludes.
While there is scope to slow the pace at which that happens, the window of opportunity to alter that trajectory has passed.
Melting ice-sheets and warmer ocean temperatures – the two main causes of sea-level rise – are being driven by past emissions.
There is a time lag between cause and effect that means policy intervention now will not make an immediate difference.
“It is virtually certain that global mean sea level will continue to rise over the 21st century in response to continued warming of the climate system,” the report states.
Over the longer term, the level will “rise for centuries to millennia due to continuing deep ocean warming and ice sheet melt, and will remain elevated for thousands of years”, it adds.
Speaking to the ‘The Conversation’ news site, climate scientist Robert Kopp, one of the lead authors of the report, said sea-level rise presented an escalating threat to coastal communities over the coming decades.
He said an increase of between six inches and a foot is “locked in” by 2050. Beyond that, the scale of sea-level rise becomes more sensitive to the world’s emissions choices, he added.
On the current path, an increase of two feet is likely by the end of the century. If the world meets the Paris agreement target of restricting global temperature rise to 2 degrees Celsius, that could be reduced to around 1.6 feet, he said.
The consequences of rising sea levels include increased flooding, coastal erosion and salinisation of the water table, the IPCC has warned. In some communities, ‘retreat’ could be inevitable and the data has stoked fears that some Pacific islands in particular could be uninhabitable by 2100.
2. Super storms increasingly likely
The report concluded that it is now an “established fact” that human behaviour has led to an increased frequency or intensity of some weather and climate extremes.
There is less certainty about the specific impacts of climate change on hurricanes, but the report’s authors suggest we are likely to see more intense, if not more frequent, storms as the climate continues to change.
While the number of cyclones is likely to stay the same or decrease slightly, the storms of the future are likely to come with higher average wind speeds and heavier rainfall, the report indicates.
“The proportion of intense tropical cyclones (Categories 4-5) and peak wind speeds of the most intense tropical cyclones are projected to increase at the global scale with increasing global warming,” it states.
Rising sea levels are also likely to increase the impact of storms for small islands, bringing more severe flooding.
3. Marine heatwaves a hazard to coral reefs
Marine heatwaves – severe but temporary spikes in ocean temperatures – are expected to become more common as the planet warms. The impact could be devastating for coral reefs, contributing to bleaching, loss of marine life and loss of ‘ecosystem services’ like flood protection.
An earlier IPCC report states such heatwaves are projected to become more commonplace and will likely “push marine organisms and ecosystems to the limits of their resilience”.
The 2021 report, published this week, adds that man-made climate change is the primary driver of these events.
“Marine heatwaves have approximately doubled in frequency since the 1980s and human influence has very likely contributed to most of them since at least 2006,” it states.
Controlling the increase in the earth’s temperature would limit, but not eliminate, the threat from marine heatwaves.
“Marine heatwaves have become more frequent over the 20th century and are also projected to increase around the globe over the 21st century,” the report adds.
Managing other coral reef stressors, such as fishing pressure and water quality, are cited as the best means to mitigate impacts.
4. Shoreline retreat to continue apace
One of the starkest and most visible impacts of climate change in the Cayman Islands might be the ‘retreat’ of the shoreline.
Recent images of water lapping against seawalls fronting condos and hotels on Seven Mile Beach aptly demonstrate the potentially devastating economic consequences of permanent beach loss to the island’s economy.
While there are other factors at play, most significantly the impact of development on the active beach, the influence of climate change cannot be dismissed.
Continued sea-level rise will mean more coastal erosion and shoreline retreat for small islands over the next several decades, the IPCC report warns.
This could happen gradually over time or as an ‘episodic event’ such as extreme storm surge wiping away chunks of shoreline.
“Shoreline retreat is projected along sandy coasts of most small islands,” the report indicates.
The IPCC notes, in an earlier report on the impact of climate change on the world’s oceans, that preserving natural features, like coral reefs and mangroves, is the best way to mitigate the impacts of coastal erosion.
Raising the height of the bottom floors of shoreline buildings, moving structures further inland and avoiding new development in low-lying coastal zones, are also highlighted as potential strategies to avoid the worst consequences of rising seas and shoreline retreat.
5. Hotter, drier conditions expected
It is no coincidence that the Cayman Islands has experienced some of the hottest, driest conditions on record over the past few years.
According to the IPCC report, this trend will continue projecting a “likely decrease in rainfall” during summer in the Caribbean.
“These drying trends will likely continue in coming decades,” the report states.
“It is very likely that most Small Islands have warmed over the period of instrumental records and continued temperature increases in the 21st century will further increase heat stress in these regions.”
Globally, droughts will become more common and more severe, the report projects.
Lower rainfall is unlikely to impact drinking water in Cayman, which comes from desalinating seawater, but it would be a problem for farmers who rely on wells to water their crops. Underground aquifers need regular rainfall to replenish themselves.