The scientists behind a landmark study on the links between oceans, glaciers, polar caps and climate have issued a stark warning to the world: drastically cut emissions or watch cities disappear due to rising sea levels, rivers will dry up and marine life will collapse.
Days after millions of young people demanded an end to the fossil fuel era in protests around the world, a new report from a United Nations-backed panel of experts found that radical action can still prevent some of the worst. possible outcomes of global warming.
Reuters reports that the study made clear that allowing carbon emissions to continue their upward path would upset the balance of the great geophysical systems that govern the oceans and the frozen regions of the Earth so deeply that no one could escape without being touched.
"Everyone in the world will be affected by rising sea levels and the other changes we are seeing," Dr Michael Meredith, an oceanographer with the British Antarctic Survey and one of the authors of the report, told Reuters.
“The key thing that comes out of the report is that we have a choice. The future is not set in stone, "he said.
Finalized on Tuesday last week in a 27-hour session of talks in Monaco between authors and government representatives, the report was the culmination of two years of work by the UN-backed Intergovernmental Panel on Climate Change (IPCC).
Compiled by more than 100 authors who analyzed 7,000 scholarly articles, the study documented the implications of warming oceans, fast-melting ice sheets in Greenland and Antarctica, and shrinking glaciers for more than 1.3 billion people living in low or high mountain regions.
The report projects that sea level could rise one meter by 2100, ten times the rate in the 20th century, if emissions continue to rise. Looking ahead, the rise could exceed five meters by 2300.
In the Himalayas, the glaciers that feed ten rivers, including the Ganges and the Yangtze, could be drastically reduced if emissions do not decrease, affecting water supplies in a swath of Asia.
Thawing permafrost in places like Alaska and Siberia could release large amounts of greenhouse gases, which could trigger feedback loops that would drive faster warming with consequent faster sea-level rise.
Reuters reports that the IPCC galvanized global concern about climate change in October when it released a report that showed the world would need to cut emissions in half over the next decade to have a chance to meet the temperature targets in the Climate Agreement. Paris 2015 sponsored by the UN.
After a subsequent report published last month on land use and agriculture, the IPCC Special Report on Oceans and the Cryosphere, or 'Frozen World', was the final piece in a scientific puzzle that revealed the global reach of climate impacts.
Launched two days after a one-day UN climate summit closed in New York with scant signs of transformative action by major economies, the latest report highlights the gulf between science warnings and the politics of the most governments.
"If we cannot take ambitious action to reduce greenhouse gas emissions, we will have these high-level impacts," said Dr. Nerilie Abram, paleoclimatologist at the Australian National University and author of the study. "We are at a point where we have to make a decision," he added.
Carbon emissions, which hit a record last year, are projected to inflict a devastating toll on the oceans, which so far have cushioned nearly all of the human warming generated by burning coal, oil and gas.
As the oceans warm, what are known as "marine heat waves" become more intense, turning coral reefs white, including much of Australia's Great Barrier Reef.
As more carbon dioxide dissolves in the water, the oceans are also becoming more acidic and damaging to ecosystems.
In turn, rising temperatures starve the upper layers of the water of oxygen, suffocate marine life, create growing dead zones and disrupt the circulation of ocean currents, unleashing a more disruptive climate on land. .
The authors say long lag times to work in the oceans mean that some of these changes will inevitably intensify for centuries, even if the world stopped emitting all its greenhouse gases tomorrow.
However, if emissions are allowed to continue to rise, the impacts are likely to begin to accelerate so rapidly that they will overwhelm the ability of societies to cope, and the poorest and most vulnerable communities and countries will succumb first.
"In a high-emissions scenario, the chances of having a reasonable foothold to cope with impacts become much smaller," said Professor Matthias Garschagen, chair of human geography at LMU Munich, another author.
"Systems are changing in a way in recent history that they have never changed before," he added.