Climate Change Takes Toll On Oceans, Ice: UN Reporthttps://phys.org/news/2019-09-climate-toll-oceans-ice_1_2.htmlLoading the atmosphere with CO2 and greenhouse gases has spawned a host of consequences, starting with irreversible sea-level rise, according to a draft
Intergovernmental Panel on Climate Change (IPCC) Special Report obtained by AFP.
Here are impacts highlighted in a summary slated for release on September 25:...EL NINOS: Extreme El Ninos—weather phenomena which drive forest fires, cause disease outbreaks and affect cyclones—are expected to double in frequency if emissions are not cut.
SUSTENANCE: Food supply from shallow tropical waters could decline by 40 percent by the year 2100 because of warming and acidification.
SEA LEVEL: Compared to the 1980-2000 period, seas will rise nearly half a metre by 2100 if Earth warms 2C above preindustrial levels, and 84 cm in a 3C-4C world.
In the 22nd century, the pace of sea-level rise is likely to jump 100-fold from 3.6 millimetres per year today to several centimetres annually.Even if global warming is capped at 2C, oceans will eventually rise several metres, submerging areas that are today home to 280 million people.
FLOOD DAMAGE: Without major adaptation efforts, the cost of annual flood damage caused by storm surges would increase 100- to 1,000-fold by 2100.
NEW NORMAL: Many low-lying megacities and small island states will experience what are today rare sea-level extremes every year by 2050, no matter how fast CO2 emissions are drawn down.
WETLANDS: Globally, 20 to 90 percent of coastal wetlands will disappear by 2100, depending on sea-level rises.
OXYGEN: The concentration of life-giving oxygen in marine environments has dropped two percent in 60 years, and will decline another three to four percent by 2100 at current rates of carbon pollution. Oxygen levels will likely decline over 59-80 percent of the ocean surface within 20 years.
CORALS: Coral reefs—a major bulwark against storm surges—will decline by 90 percent even in a 1.5 C world. Two degrees would be a death sentence for corals, which underpin the livelihoods of half a billion people today.
GLACIERS: Average annual runoff from glaciers in most mountain regions will have peaked and begun to decline by 2100. Worldwide, more than two billion people today depend on glaciers for fresh water.
PERMAFROST: Thirty to 99 percent of the world's top-layer permafrost—the top three metres—could melt by 2100 if carbon pollution continues unabated, releasing a carbon bomb of greenhouse gases. If emissions are aggressively capped, the area thawed could be vastly reduced.
and many others ...
https://www.ipcc.ch/report/srocc/