by Andrew Glikson
“Without major action to reduce emissions, global temperature is on track to rise
Whether
anything can be done by humans to arrest or reverse global warming and its consequences for the habitability of planet Earth remains an open question, for which neither climate science nor the ignorant hordes of politicians and economists, oblivious to the basic laws of physics, have the answer. However, it is likely that over the next centuries or longer the flow of cold water from the melting of the Greenland and Antarctica ice sheets will lead to a
transient slowdown of the rate of warming before the large ice sheets are exhausted.
Having ignored climate science, dismissed climate scientists and repeatedly confected untruths, while global
heating accelerates with deleterious consequences, Homo “sapiens” finds itself on track toward carbon poisoning of the atmosphere, the lungs of the
inhabitable Earth, acidification of the hydrosphere and coating of the land with carbon and plastics.
In a new paper, a group of leading climate scientists (
Hansen et al., 2023) indicates mean global temperature is currently accelerating toward 2.0
°C above pre-industrial temperature by the middle of the decade (Figure 1). The Arctic is warming nearly
four times faster than the rest of the world over the last 43 years, on average around 3℃ warmer than it was in 1980. Over the past 30 years Antarctica has been one of the fastest-changing places on Earth, warming more than
3 times faster than the rest of the world.
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[ Figure. 1. Global temperature relative to 1880-1920 based on the GISS
(Goddard Institute of Space Studies) analysis - by James Hansen et al., 2023. ] |
As the polar regions warm, the tropical climate zones expand and the mid-latitudes, where the most fertile soils are and where the bulk of the population lives, are contracting.
Thus (Figure 2.):
- Agro-climate zones in eastern Europe experienced a northward migration velocity of 100 km per 10 years over the past 40 years.
- Northward migration of climate zones in Europe may be up to two times faster in the next decades.
- Negative impacts of heat stress are expected to non-linearly increase in large parts of southern and southeastern Europe.
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[ Figure 2. (a) Agro-climate zonation of Europe based on growing season length (GSL) and active temperature sum (ATS) for the period between 1975 and 1995.The identified agro-climate zones are named as follows (going from north to south): boreal north (BON), boreal south (BOS), nemoral (NEM), continental (CON), Pannonian (PAN), northern maritime (NMA), southern maritime (SMA) and Mediterranean (MED). (b) The migration of agro-climate zones between the 1975–1995 and 1996–2016 periods. For better distinction, only the areas affected by migration of agro-climate zones are displayed (colored areas), while gray color denotes the areas where the agro-climate zones have not changed - Ceglar et al. 2019. ]
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A
projection by NOAA states:
“While we cannot stop global warming overnight, we can slow the rate and limit the amount of global warming by reducing human emissions of heat-trapping gases and soot (“black carbon”). This projection takes neither the amplifying feedback, i.e. from warming of the oceans, melting ice sheets,
melting of the permafrost, migrating climate zones, nor the time factor into account.
Factors rendering a potential reversal of global warming in the short term unlikely include:
A factor
rarely taken into account emerges from the key paper
“Ice melt, sea level rise and superstorms: evidence from paleoclimate data, climate modelling, and modern observations that 2°C global warming could be dangerous”, by
Hansen et al. (1996) (Figure 3.).
Here the flow of cold ice-melt water results in formation of large cold pools in the Atlantic Ocean and Southern Ocean (Figure 3), related to an overall decline in mean global temperatures to -0.33
°C by 2096 (Figure 4.) due to the flow of cold ice-melt water from Greenland and Antarctica.
While the collision between the cold air and water fronts and the tropical war air mass would lead to intense storms over large tracts of Earth, such transient cooling may allow Home "sapiens" a respite from global warming before its home becomes an
uninhabitable planet.
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| [ Figure 4. Surface air temperature (◦C) relative to 1880–1920 in (a) 2065, (b) 2080, and (c) 2096. Top row is IPCC scenario A1B. Ice melt
with 10-year doubling is added in other scenarios - James Hansen et al. 2016. ] |
A/Prof. Andrew Y Glikson
Earth and Paleo-climate scientist
