Had 19th-century scientific minds possessed contemporary instrumentation for atmospheric investigation, they might have discerned the nascent indicators of a significant environmental transformation: industrial pursuits, such as the combustion of coal and wood, had commenced altering the global climate.
Through a recent conceptual investigation, a cadre of Earth and atmospheric scientists determined that, equipped with appropriate technological apparatus, the initial phases of this climatic evolution could have been hypothetically identified circa 1885, presaging the advent of vehicles powered by fossil fuels.
Their findings imply that a discernible human imprint upon atmospheric temperature has likely been present for upwards of 130 years.
In actuality, the thermal retention capabilities of carbon dioxide were only beginning to be understood in the mid-19th century. The output of this atmospheric constituent was escalating due to the Industrial Revolution on the European continent, and it was not until the 1970s that rigorous scientific inquiries truly commenced to elucidate its role—and our culpability—in contemporary climatic alterations.
Within their simulated framework, the investigators posited that scientists possessed the capacity for precise global atmospheric change measurements from 1860 onward, furnished with instruments as dependable as present-day satellite microwave radiometers and contemporary assessments of carbon dioxide fluctuations derived from ice cores and stratospheric probes.
“Subsequently, a methodology employing a characteristic ‘fingerprint’ is applied to differentiate between anthropogenic and natural climatic influences,” the researchers articulate.
Notwithstanding the overarching warming impact of greenhouse gases, the initial harbinger of climate change would have manifested as stratospheric cooling. This phenomenon represents a direct radiative consequence of human-induced emissions of carbon dioxide and other greenhouse gases, coupled with ozone depletion attributable to human agency.
Greenhouse gases impede the escape of thermal radiation from the Earth’s surface into the lowest atmospheric stratum, the troposphere. These gases augment the reflectivity of the adjacent layer, the stratosphere, thereby deflecting thermal energy back towards the planet.
Concurrently, a reduction in stratospheric ozone diminishes that layer’s capacity to absorb radiative heat. The cumulative effect is a cooling of the stratosphere, while concurrently, the troposphere beneath begins to experience warming.
Furthermore, the stratosphere is less susceptible to the transient meteorological conditions prevailing in the troposphere below, a factor that complicates the identification of enduring climatic trends from ground-based observations.
“A pronounced cooling of the middle to upper stratosphere, predominantly instigated by anthropogenically elevated carbon dioxide levels, would have been discernible with a high degree of certainty by approximately 1885, predating the widespread adoption of gasoline-powered automobiles,” the authors note.
“Even if our observational capabilities in 1860 were not globally comprehensive, and robust stratospheric temperature data pertained solely to mid-latitude regions of the Northern Hemisphere, it would still have been feasible to detect human-induced stratospheric cooling by 1894, merely 34 years subsequent to the hypothetical commencement of atmospheric monitoring.”
Absent the invention of a temporal displacement device, it remains an unanswerable question whether such prescience would have averted the deleterious repercussions of unmitigated fossil fuel consumption throughout the 20th and 21st centuries, the ramifications of which are only now becoming acutely apparent. For at least half a century, knowledge of climate change has been extant, yet humanity has not yet devised a means to extricate itself from its dependence on fossil fuels.
“We ascertain with a substantial degree of confidence that sustainable trajectories are imperative to obviate perilous anthropogenically driven interference with the climate system. For the middle to upper stratosphere and the troposphere, the anticipated future alterations over the ensuing 26 years are projected to exceed the simulated modifications observed during the 39-year interval from 1986 to 2024,” the researchers conclude.
“Humankind now stands at the precipice of dangerous anthropogenic disruption. Our immediate decisions will dictate whether or not we transcend this critical threshold.”
