Climate Change: Scientists Could Have Detected Human Impact as Early as 1885

A recent study indicates that scientists,equipped with 19th-century technology equivalent to modern tools,could have identified the initial signs of climate change as early as 1885. This detection would have been possible by observing the cooling of the stratosphere, a direct outcome of human activities like burning coal and wood. The findings suggest that human influence on atmospheric temperature has been discernible for over 130 years.

Early Detection of Climate Change: A Hypothetical Scenario

The research team’s thought experiment involved assuming that scientists in 1860 possessed the capability to accurately measure global atmospheric changes. This included using instruments as reliable as today’s satellite microwave radiometers and having access to contemporary estimates of carbon dioxide changes derived from ice cores and stratospheric balloons.

Did You No? The Industrial Revolution, which began in the late 1700s, significantly increased carbon dioxide emissions due to the burning of fossil fuels.

Researchers then applied a pattern-based “fingerprint” method to distinguish between human and natural impacts on the climate. Despite the overall warming effect of greenhouse gases, the early warning sign of climate change would have manifested as stratospheric cooling, a direct radiative response to human emissions of carbon dioxide and other greenhouse gases, as well as human-driven ozone loss.

The Role of Greenhouse Gases and Ozone Depletion

Greenhouse gases trap radiation from the Earth’s surface within the troposphere, the lower layer of the atmosphere. These gases enhance the reflective power of the stratosphere, causing heat to bounce back towards Earth. Together, ozone depletion reduces the stratosphere’s capacity to absorb radiative heat.The combined effect results in stratospheric cooling and tropospheric warming.

The stratosphere’s relative isolation from tropospheric weather patterns makes it an ideal location for observing long-term climate trends. According to the study, significant cooling of the mid- to upper stratosphere, primarily driven by increased carbon dioxide levels, could have been confidently identified by approximately 1885, predating the widespread use of gas-powered cars.

Pro Tip: Monitoring stratospheric temperatures provides valuable insights into the long-term effects of greenhouse gas emissions on the Earth’s climate system.

Implications and future Projections

Even with limited monitoring capabilities in 1860, such as high-quality stratospheric temperature measurements available only for Northern Hemisphere mid-latitudes, human-caused stratospheric cooling could have been detected by 1894, a mere 34 years after the hypothetical start of climate monitoring.

The researchers emphasize that enduring pathways must be pursued to avert perilous human-induced climate interference. Projected changes in the stratosphere and troposphere over the next 26 years are expected to surpass the changes observed between 1986 and 2024. Humanity stands at a critical juncture, where near-term decisions will determine whether or not we cross the threshold of dangerous anthropogenic interference.

The study was published in PNAS.