Understanding The UN’s Newest Report On Climate Change And The Oceans

The world is changing. Whether we’re talking about the speed with which consumer technology has reconfigured human communication within a matter of decades, or how the global food supply chain is irrevocably shifting the human diet for better and for worse, the world of 100, 50, even 10 years ago is gone. Some of these changes, while challenging, are welcome: extreme poverty has been significantly reduced in the past 50 years; global teen pregnancy rates have fallen; maternal and child mortality rates have fallen; and global life expectancy has risen significantly.

But all is not well with our changing world. Human-driven climate change is, as so many world leaders have reminded us, an existential threat. The hottest years on record have all occurred in the past 20 years. We’re facing a mass extinction event unlike any before — completely driven by human activity. And a new U.N. report on climate change’s effects on the ocean and cryosphere casts into stark relief just how rapidly we’re reaching a crisis point.

But what does this mean, exactly? We break it down.

What does the U.N. report say?

First, what the report is: a meta-analysis of over 7,000 papers on the effects climate change is having on the ocean and the cryosphere (which translates to “the components of the Earth System at and below the land and ocean surface that are frozen, including snow cover, glaciers, ice sheets, ice shelves, icebergs, sea ice, lake ice, river ice, permafrost, and seasonally frozen ground”). Basically: over 100 researchers from around the world looked at how our global water systems are being affected by climate change.

Here’s what they found:

  • Marine heatwaves, which lead to bird and fish population die-offs, “doubled in frequency and have become longer-lasting, more intense and more extensive”
  • The ocean is absorbing “20-30%…of total anthropogenic CO2 emissions” which is worsening ocean acidification
  • Ice flow and retreat (or: rapidly melting glaciers that are not refreezing) in Antarctica is accelerating, which is directing leading to rising sea levels
  • Sea ice loss in the Arctic has increased wave size, and “extreme wave heights, which contribute to extreme sea-level events, coastal erosion and flooding, have increased” in the Atlantic Ocean
  • Permafrost thaw has increased at an unprecedented rate, which is releasing methane into the atmosphere
  • “Glacier retreat and snow cover changes have contributed to localized declines in agricultural yields in some high mountain regions”
  • Carbon sinks such as seagrass meadows are dying off as the ocean heats up
  • Phytoplankton blooms are occurring earlier in polar regions and disturbing the global marine food web structure and biodiversity; simultaneously, phytoplankton populations are decreasing

Translation: yikes.

What does this mean in plain English?

The report, according to Dan Laffoley of the International Union for Conservation of Nature, can be summed up thusly: “We are an ocean world, run and regulated by a single ocean, and we are pushing that life support system to its very limits.”

Basically what this means is: we’re in deeper trouble than any of us anticipated. This is part of a larger trend of extremely alarming reports about mass extinction, rising temperatures, threats to essential food sources, and more.

In short: the ocean is heating up and becoming less oxygen-rich, leading to massive die-offs and direct threats to marine populations and the populations that rely on them. As for the cryosphere: as the world heats up, ice sheets melt and do not re-freeze, leading to a negative feedback loop that is creating more intense storms, coastal erosion, and increasing acidification, which also leads to die-offs.

In terms of interior cryospheres (such as, say, mountain glaciers that provide fresh water — think the watershed fed by Mount Hood in Oregon), as the world heats up, snowpack melts earlier. Winter precipitation events are more likely to be rain rather than snow, which means that the snowpack is not replenished as readily, which in turn negatively impacts water supplies and water quality. In other words: the global freshwater supply is dwindling, and worsening climate change conditions are creating a negative feedback loop which is making it increasingly difficult to maintain snowpack levels and prevent drought.

Here are some things the report anticipates happening:

  • As glaciers melt and sea levels rise, historic flooding will become common.
  • Marine populations, such as fish, will disappear — especially populations which are food sources for humans
  • Wildfires will increase
  • Permafrost thaw will release methane, which will create a feedback loop of heating and thawing, and will have a direct, negative impact on food and water security
  • Phytoplankton — which produce the large majority of the world’s oxygen — will die off at an increasing rate, meaning more carbon dioxide will be trapped in the atmosphere and the marine food supply chain will be negatively disrupted