Climate change burst into public attention

 

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Climate change burst into public attention with climate anomalies in 1988 so extreme that Time Magazine declared Earth to be “person of the year.” Rising public interest in climate change, especially the role of humanity in causing change, led to the 1992 United Nations Framework Convention on Climate ChangeFootnote4 and a large increase in funding for climate observations and research. The Framework Convention aimed to prevent dangerous human-caused climate change. The largest funding increase was for a NASA program initially titled Mission to Planet Earth expected to make global observations needed to understand ongoing global change.

Sidebar 1. Global surface temperature relative to 1880-1920 in  is the GISS (Goddard Institute for Space Studies) analysis through October 2024.2 The 1970-2010 warming rate of 0.18 °C/decade almost doubled in 2010-2023, but this higher rate is not a prediction of the future. A downturn in greemissions could alter projections on decadal time scales.

By 1992 it was understood that two things caused large human effects on climate: greenhouse gases (GHGs) and aerosols (tiny, generally microscopic, particles suspended in the air). GHGs cause global warming by holding in Earth’s heat radiation, acting like a blanket. The physics of this greenhouse effect is well understood and tested, for example, by comparison of Mars, Earth and Venus, with their differing amounts of atmospheric GHGs. Carbon dioxide (CO2), produced mainly by burning of fossil fuels (coal, oil and gas) but also by deforestation, causes more than half of the human-made greenhouse warming. Human-made increases of CO2 and the other main GHGs (Sidebar 2) have long lifetimes in the atmosphere from decades to millennia. Thus, these gases are well-mixed in the atmosphere and it is easy to measure their changing global amounts.

Human-made aerosols with greatest effect on climate are products of fossil fuel burning and biofuels (like firewood). Most aerosols increase reflection of incoming sunlight back to space and thus have a global cooling effect. Charlson and colleaguesFootnote5 concluded in 1992 that the climate forcing by aerosols – the cooling drive for climate change, see below – was similar in magnitude to the GHG forcing, but opposite in sign, thus tending to offset GHG warming. Aerosol offset of GHG warming is a Faustian bargain (),Footnote6 that is, a bargain providing present benefit without regard to future consequences. The aerosols providing a cooling benefit are also inherently dangerous particulate air pollution responsible today for several million annual deaths by respiratory, cardiovascular, and even neurological diseases worldwide;Footnote7 thus, as global pollution control has improved and clean energies are introduced the cooling effect of aerosols is lost: with the change of ship regulations, our first Faustian payment came due.Footnote

Figure 2. Faustus contemplates bargain with Mephistopheles, who offers him his present desire at the cost of future detriment, much like the cooling benefit of aerosols, which extract a cost in rapidly increased global warming once society no longer tolerates unhealthy air pollution.