Today marks 1 month of Trump's Presidency. He is doing a great job!
However, what is Climate Change?
Since the 1970s much research has focused on global warming with the consensus that human activity is the most likely principal protagonist. The IPCC, which was formed in 1988 to study the problem, predicted the likelihood as greater than 90% in its 4th Assessment Report (IPCC AR4, 2007). The factors responsible are now well documented with the Industrial Revolution the genesis due to rural to urban migration, the introduction and adoption of coal-fired steam engines, and the concomitant release of CO2, whose atmospheric longevity equates to more than 100 years. Following the West's lead, similar events are now taking place in modern-day China (together with India and the African continent) where massive rural-to-urban migration is leading to industrialization on an unprecedented scale.
The Greenhouse Effect and its Causes
Svante Arrhenius (1896) was the first to use the basics of chemistry to estimate the effect of increases in CO2 on surface temperatures, and this led Charles David Keeling (1958) to conclude that human-caused CO2 emissions (F in the Kaya Identity) are high enough to cause global warming.
The physical science basis is well established and has been documented for many years. Carbon dioxide acts like an atmospheric blanket to minimize solar radiation exit to the outer atmosphere, so the planet warms with the result of an average surface temperature of 17C. Since the Industrial Revolution, atmospheric CO2 concentrations have increased progressively from around 280 parts per million (ppm) to some 426 ppm as recorded in June 2024. With a time lag between concentration and temperature, scientists have predicted that a further 0.5C warming is imminent - bringing average land temperatures up from 1.55C above a 1900 baseline to over 2C.
One thing to bear in mind, however, is that recent pollution - in particular from aerosols caused by China, India, and North Africa - has a cooling effect on temperatures. Hopefully, as these countries and regions develop further, environmental regulations will be promulgated and pollutants (and concomitant aerosols) reduced. However, this will mean more warming is in store.
Unfortunately, as mentioned above, CO2 is not the sole 'greenhouse gas' and coal is not the only pollutant. Six gases: CO2; CH4; N2O; CFC-11; HFC-134a; and CF4 have been identified with 'global warming potential', which is simply a calculation of the greenhouse effect caused by the release of a kilogram of gas, relative to that produced by an equivalent volume of CO2.
Methane (CH4) is perhaps the next focus and, in terms of warming, is up to 30 times more potent than CO2 (although volumes are smaller). Methane comes from a variety of sources including humans and ruminants, landfill sites, and paddy fields, all of which are increasing as the global population rises.
Since the beginning of the 20th Century, oil consumption has been on an ever-increasing scale, and this, too, together with other fossil fuels, such as coal and natural gas, contributes to global warming.
Finally, deforestation and agricultural land use also play important roles. Around 20% of human-induced CO2 emissions are now attributed to deforestation with countries such as Brazil and Indonesia providing the principal outputs. Paddy fields and the increasing demand for rice are also adding to the problem. Despite these, in terms of scale and impact, coal still presents the biggest problem and, as the largest global energy source, is an increasing problem. So, while coal is the major culprit here, we should also not ignore other factors' contributions.
Impacts
The time frame for impacts does not look good. We already witness more frequent freak weather conditions with a 1.55C rise in temperature recorded since 1900.
Unchecked, global temperatures will continue to rise since oceans and biospheres absorb as little as 50%. In any case, oceans are set to become more acidic and there is concern that absorption will decrease with time. This global warming will then affect climate change step-changes and 'tipping points' will result. These tipping points occur when temperatures reach critical points that trigger further releases of inimical gases. There is concern that rising temperatures, for example, could mediate trapped methane release from permafrost or beneath the oceans. Since our knowledge of this area is lacking, further study is warranted.
Feedbacks
Warming is amplified or ameliorated by positive and negative feedback, respectively.
Positive feedbacks include: the ice-albedo feedback where, when ice melts, darker exposed ocean surfaces absorb more radiation; and the water-vapor feedback where a warmer atmosphere holds more water vapor, which is itself a greenhouse gas and leads to further warming. One negative feedback is the lapse-rate feedback where a warmer atmosphere radiates more solar power to space. Therefore, as the atmosphere warms, the enhanced radiation offsets some of the initial warming. Feedback such as cloud feedback is the summation of two opposing effects. While reflected sunlight reduces energy input, surface-emitted absorbed infrared radiation decreases energy loss, and the temperature increases.
A complicating factor is time with both rapid and protracted feedback apparent. Most are relatively rapid but carbon cycle feedback is a long-term possibility. This is characterized by initial warming, which affects the release of frozen CO2 and CH4 which, in turn, contributes to warming and further gas release.
Summary
Although we can look for answers to our destiny in The Holy Bible, and listen to church leaders, President Trump would also be wise to listen to his trusted scientific advisers on matters of climate. Time is running out.
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