A new study published in the journal Nature suggests that the difference between a scenario where the Earth will be warmed by upto 1.8 degrees Celsius by the end of the 21st century and a scenario where the Earth will be warmed by upto 3.6 degrees Celsius depends on the social system.
In other words, public perceptions of climate change, the future cost and effectiveness of climate mitigation and technologies, and how political institutions respond to public pressure are important determinants of the degree to which the climate will change over the 21st century, a press release issued by the University of California Davis noted.
When it comes to global warming, one of the most prominent temperature-control goals is the figure of 1.5 degrees Celsius, which is the target set out by the 2015 Paris Climate Agreement that was signed by 195 countries in 2015.
This agreement has set out a goal to limit climate change in the coming decades. The agreement aims to slow the process of global warming by making efforts to “hold the increase in the global average temperature to well below 2 degrees above pre-industrial levels and to pursue efforts to limit the temperature increase to 1.5 degrees above pre-industrial levels”.
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As of today, human activities have already caused global temperatures to rise by about 1 degree Celsius above pre-industrial levels (1950-1900). Significantly, countries’ emissions targets so far are not in line with limiting global warming to under 1.5 degrees.
Another study published in Nature in September 2021 said that the global oil and gas production should decline by three percent per year until 2050 to keep global warming to below 1.5 degrees Celsius.
In August 2021, independent charitable organisation Oxfam said that the ‘net zero’ carbon targets that many countries have been announcing may be a “dangerous distraction” from the priority of cutting carbon emissions.
Net-zero, also referred to as carbon-neutrality, does not mean that a country would bring down its emissions to zero. That would be gross-zero, which means reaching a state where there are no emissions at all, a scenario hard to comprehend. Net-zero is a state in which a country’s emissions are compensated by absorption and removal of greenhouse gasses from the atmosphere.
Oxfam said that to limit global warming below 1.5 degrees Celsius and to prevent irreversible damage from climate change, the world needs to collectively be on track and should aim to cut emissions by 45 percent by 2030 from 2010 levels.
What the study says
The recent study simulated 100,000 possible future policy and emissions trajectories to identify the variables that are relevant to the climate-social system that are likely to impact climate change through this century.
Overall, these trajectories fell into five clusters, with warming varying between 1.8 and 3.6 degrees Celsius above the 1880-1910 average in the year 2100. The study says that there is a “strong probability” of warming between 2 and 3 degrees Celsius at the end of the century.
These five possibilities suggest that none of them meet the Paris Climate Agreement’s target of limiting warming to 1.5 degrees Celsius. But the authors do suggest that there is a substantial chance of meeting the 2 degrees Celsius target.
The key drivers of how climate change will shape up include people’s perceptions and social groups, the improvements in mitigation technology over time and the responsiveness of political institutions. These key drivers trump individual actions, as per the study.
“Small changes in some variables, like the responsiveness of the political system or the level of public support for climate policy, can sometimes trigger a cascade of feedbacks that result in a tipping point and drastically change the emissions trajectory over the century,” lead author of the study Frances C. Moore, who is an assistant professor with the UC Davis Department of Environmental Science and Policy was quoted as saying.
Essentially the authors are saying that while scientists make projections related to climate change, they should also take into account the effects of climate policy and social change.