2023-11-02 12:52:02
Melting ice in Greenland – A PHOTO
MADRID, 2 Nov. (EUROPA PRESS) –
An article published in ‘Oxford Open Climate Change’ warns that strategies to combat climate change will have to include more than just reducing greenhouse gases.
This is clear from an analysis of climate data led by researcher James Hansen, director of the Program on Science, Awareness and Climate Solutions, of the Columbia University Earth Institute.
Scientists have known since the 19th century that infrared-absorbing (greenhouse) gases warm the Earth’s surface and that the abundance of greenhouse gases changes naturally, as well as by human action.
Roger Revelle, one of the first scientists to study global warming, wrote in 1965 that industrialization meant that humans were carrying out a “vast geophysical experiment” by burning fossil fuels, which added carbon dioxide (CO2) to the atmosphere. air. Currently, CO2 has reached levels that have not existed for millions of years.
A long-standing question is how much global temperature will increase with a given increase in CO2. A study published in 1979 by the National Academy of Sciences of the United States concluded that doubling atmospheric CO2 with fixed ice sheets would probably cause global warming of between 1.5 and 4.5° Celsius.
This was a very wide range, to which was added the uncertainty about the delay in warming caused by the Earth’s enormous ocean.
This new work reassesses climate sensitivity based on improved paleoclimate data, and concludes that the climate is more sensitive than commonly assumed. Their best estimate for the doubling of CO2 is global warming of 4.8°C, significantly higher than the United Nations Intergovernmental Panel on Climate Change’s best estimate of 3°C.
The authors also conclude that much of the predicted warming from greenhouse gases over the past century has been offset by the cooling effect of human-made aerosols, i.e. fine particles suspended in the air.
The amount of aerosols has decreased since 2010 as a result of reduced air pollution in China and global restrictions on aerosol emissions from ships.
This reduction in aerosols is good for human health, since particulate air pollution kills several million people a year and negatively affects the health of many more. However, aerosol reduction is beginning to unmask greenhouse gas warming. which had been hidden by the cooling of the aerosols.
Authors have long called aerosol cooling a “Faustian bargain” because, as humanity eventually reduces air pollution, the payoff comes in the form of increased warming.
This new paper predicts that an acceleration of post-2010 global warming above the level of natural climate variability will soon become evident. The 1970-2010 global warming rate of 0.18°C per decade is projected to increase to at least 0.27°C per decade during the decades after 2010. As a consequence, the global warming level of 1.5 °C will be exceeded this decade and 2 °C in the next two.
In a final section, Hansen describes his perspective based on decades of experience trying to influence government policy.
Firstly, it believes that to achieve a rapid reduction in CO2 emissions it is necessary to increase the national carbon tax and apply a border tax on products from countries that do not apply it, as well as support modern nuclear energy as a complement. of renewable energies.
Second, it argues that the West, primarily responsible for climate change, must cooperate with developing nations to help them achieve energy trajectories consistent with a conducive climate for all.
Third, even with these efforts, Hansen believes that global warming will reach levels with dangerous consequences; He argues that we must also conduct research and development for temporary, purposeful actions to address the Earth’s now enormous energy imbalance.
A decade ago, Hansen observed that the Earth was energetically imbalanced by 0.6 W/m2 (watts per square meter). Much more energy entered (absorbed sunlight) than exited (heat radiation to space).
That excess, which is the proximate cause of global warming, is equivalent to 400,000 Hiroshima atomic bombs a day, and most of that energy ends up in the ocean. Now, due in large part to the decline in aerosols, the imbalance has doubled to approximately 1.2 W/m2.
This enormous imbalance is the proximate cause of accelerated warming of the planet and increased melting of polar ice, which will likely disrupt ocean circulations and cause rapid sea level rise by the end of this century.
The paper argues that such action will be essential to avoid the further geotransformation that will occur in the absence of such action. Possible actions include stratospheric aerosol injection, for which volcanoes provide relevant but inadequate test cases, and ocean saltwater spraying by autonomous sailboats in regions susceptible to cloud seeding.
Hansen suggests that young people focus on an underlying problem that has developed in Western democracies, especially the United States. “The ideal of one person/one vote has been replaced by that of one dollar/one vote,” argued Hansen.
“Special financial interests, like the fossil fuel industry, the chemical industry, the logging industry, the food industry, for example, are allowed to buy off politicians – they warn – . No wonder the climate is out of control, that environmental toxicity is in the process of exterminating insects, including pollinators, that forests are poorly managed and that agriculture is designed for profitnot for the nutrition and well-being of the public.
“We live on a planet with a climate characterized by delayed response, which is a recipe for intergenerational injustice,” Hansen warns. “Young people must understand this situation and the actions necessary to ensure a bright future for themselves and their children.” .
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