Atmospheric effects of CO2 become more significant as more is released

‘Future increases in CO2 will provide a more potent warming effect on climate than an equivalent increase in the past,’ explains Haozhe He, the lead author of a new study undertaken at the University of Miami Rosenstiel School of Marine, Atmospheric and Earth Science.

‘This new understanding has significant implications for interpreting both past and future climate changes and implies that high CO2 climates may be intrinsically more sensitive than low CO2 climates.’

As the Conference of Parties meet for the 28th time in the UAE, new research suggests that carbon dioxide becomes a more potent greenhouse gas as more of it is released into the atmosphere and, despite the recent efforts of some climate change deniers to convince the public that CO2 is a benign, if not beneficial element, the fact remains that it leads to global warming by trapping heat energy in the climate system.

In this study, the researchers used state-of-the-art climate models and other tools to analyse the effect increasing CO2 has on a region of the upper atmosphere — the stratosphere — that scientists have long known cools with increasing CO2 concentrations. They found that this stratosphere cooling causes subsequent increases in CO2 to have a larger heat-trapping effect than previous increases, causing carbon dioxide to become more potent as a greenhouse gas.

The amount of heat trapped in the atmosphere from a proportionate increase in CO2, which scientists refer to as radiative forcing, has long been thought of as a constant that does not change over time. However, as Ryan Kramer, a physical scientist at the National Oceanic and Atmospheric Administration’s Geophysical Fluid Dynamics Laboratory explains, ‘This new finding shows that the radiative forcing is not constant but changes as the climate responds to increases in carbon dioxide.’

‘Our finding means that as the climate responds to increases in carbon dioxide, carbon dioxide itself becomes a more potent greenhouse gas’ said the study’s senior author Brian Soden, a professor of atmospheric sciences at the Rosenstiel School. ‘It is yet further confirmation that carbon emissions must be curbed sooner rather than later to avoid the most severe impacts of climate change.’