GENEVA – A landmark climate report released this morning by the United Nations says that global warming is not only progressing and worsening but that it cannot be stopped over the next 30 years. An increasingly hotter future with all its consequences is basically sealed according to scientists involved in the report. The report says that a narrow window still exists to prevent the most devastating effects of a hotter climate.
The report is titled Climate Change 2021: The Physical Science Basis and was produced by Working Group I of the Intergovernmental Panel on Climate Change (IPCC) composed of hundreds of top scientists and policymakers around the world. The current report neither minces words nor hedges on the science.
The IPCC is the group that identifies and defines the scientific consensus on climate issues. The current report is the most recent report since the last issuance of a similar report 8 years ago and uses an abundance of plain language to convey its findings while also presenting scientific findings with data.
The report says that nations have been using fossil fuels at a rate and for so long that a global rise in temperatures in unavoidable in the next 30 years. That is that the greenhouse gases we have already released in the atmosphere, primarily through the use of fossil fuels since the Industrial Revolution of the 19th century, have already heated the planet by approximately 2 degrees Fahrenheit or 1.1 degrees Celsius and will continue to do so. The planet is heating faster than any other period in the past 2,000 years.
The Intergovernmental Panel on Climate Change (IPCC) used the clearest and strongest unambiguous language possible to assert that humans are responsible for climate change. Period. The first line of the report reads:
It is unequivocal that human influence has warmed the atmosphere, ocean, and land. Widespread and rapid changes in the atmosphere, ocean, cryosphere, and biosphere have occurred.
IPCC co-author Friederike Otto, a climatologist at the University of Oxford, told Reuters, “There is no uncertainty language in this sentence, because there is no uncertainty that global warming is caused by human activity and the burning of fossil fuels.”
As for the consequences of human activity on climate, the report notes that extreme weather events will become both more certain and more extreme. It adds that the impact would be widespread from heat extremes to precipitations events and loss of arctic ice.
Unlike previous reports, today’s IPCC report provides numbers that place context on the global warming trend such as extreme storms could drop 30% more rainfall in one day and be three times more frequent. Heatwaves happening 40 times more often or severe droughts occurring four times more frequently.
These are associated with an overall pattern that “climate zones have shifted poleward in both hemispheres, and the growing season has on average lengthened by up to two days per decade since the 1950s in the Northern Hemisphere extratropics.” The result is more frequent and severe heat waves that previously occurred once in 50 years are no occurring once a decade. This is accompanied by increased severity of droughts and longer, more intense fire seasons with added heat and high winds.
Another report author Carolina Vera, a physical climate scientist at the University of Buenos Aires and Argentina’s main agency for science research (CONICET: Consejo Nacional de Investigaciones Científicas y Técnicas or the National Scientific and Technical Research Council) told Reuters that there is also an increasing likelihood that multiple extreme weather events could happen at the same time.
The report notes that sea levels will rise inevitably. Regardless of any immediate intervention, the warming oceans will continue to expand accompanied by polar ice melt. The Arctic is warming at least twice as quickly as other parts of the world. In other words, the warming is accelerating.
Thus, the report notes that Arctic summer could soon be free of ice and the summer sea ice may vanish completely, at least occasionally, by 2050. The removal of sea ice produces a secondary consequence to simply melting water. Ice is reflective while seawater is dark, causing even faster and greater warming.
The IPCC report adds that,
Human influence is very likely the main driver of the global retreat of glaciers since the 1990s and the decrease in Arctic sea ice area between 1979–1988 and 2010–2019 (about 40% in September and about 10% in March). There has been no significant trend in Antarctic sea ice area from 1979 to 2020 due to regionally opposing trends and large internal variability. Human influence very likely contributed to the decrease in Northern Hemisphere spring snow cover since 1950. It is very likely that human influence has contributed to the observed surface melting of the Greenland Ice Sheet over the past two decades, but there is only limited evidence, with medium agreement, of human influence on the Antarctic Ice Sheet mass loss.
The report notes that even if the world halted global warming to 1.5C, the average sea level rise will be between 6 to 10 feet (2-3 meters) with more possible. Coastal flooding is already prevalent in many low-lying areas such as South Florida, Louisiana, and the northern Adriatic Sea. The report repeats “virtually certain that the global upper ocean (0–700 m) has warmed since the 1970s and extremely likely that human influence is the main driver.”
The report continues with sobering statements beyond the 30-year horizon and looks even grimmer. Scientists noted that sea-level rise could be as high as 15 meters (nearly 50 feet) by 2300 C.E. Such a rise could completely re-shape low-lying landmasses such as Florida, parts of Eastern China, South Pacific islands, regions across the Indian Ocean.
In the US, the National Oceanic and Atmospheric Administration’s (NOAA) administrator Richard Spinrad, Ph.D., issued a statement, “Today, scientists from across the globe delivered the most up-to-date assessment of the ways in which the climate is changing. It is a sobering IPCC report that finds that human influence is, unequivocally, causing climate change, and it confirms the impacts are widespread and rapidly intensifying.”
Dr. Spinrad added, “NOAA will use the new insights from this IPCC report to inform the work it does with communities to prepare for, respond to, and adapt to climate change. In fact, NOAA is already working directly with communities to increase their resilience to climate impacts.”
There is some good news, however. The report does note that targets for the cessation of fossil fuel use, such as a zero-carbon goal by 2050, could limit the impact of warming. That goal would involve switching to alternatives sources of energy that could include a portfolio of sources with solar, wind, and hydro. Then using that electricity to power homes and cars.
However, if little or nothing is done to create zero emissions, the report concludes that beyond the 30-year horizon, the current trend could produce a very different world than the one today in less than a century.