Words By Jasmine Crowhurst
The UN’s climate science body published a major report on August 6th, detailing the physical changes happening to our planet and the changes projected to occur because of human activity.
This is The Intergovernmental Panel on Climate Change, or IPCC’s, first report since 2013, looking at the physical science of climate change – a fundamental leap in the developments of climate science for the years ahead.
It states that the influence of humans on the climate system is “clear” as authors conclude that it is “unequivocal” that humans have warmed the planet, causing “widespread and rapid” changes to Earth’s oceans, ice, and land surfaces.
The report is one of three, outlining the impacts of global emission scenarios compared to current levels. The entire report is due in 2022 and will detail how to adapt to the impacts and prevent worst case scenarios.
One of the key developments since the last report in 2013 is the strengthening of the links between human-caused warming and extreme weather changes, which authors now say is “an established fact”. Human activities are the main drivers of more frequent or intense weather such as heatwaves, glaciers melting, ocean warming and acidification.
For the first time, the report has included the influence of aerosols, particulate matter, and methane, or ‘short lived climate forcers’. Methane, released into the atmosphere from coal mines, farming and gas and oil operations, has a global warming impact 84 times higher than CO2 over two decades and is responsible for almost a quarter of global warming.
The ambitious 1.5 degrees celsius warming limit set by the Paris Agreement in 2015 is projected to be passed by 2040. Rapid warming of almost everywhere on earth is happening and has reversed a long-term trend of global cooling. Under all emissions scenarios outlined in by the IPCC, the earth’s surface warming is projected to reach 1.5C or 1.6C in the next twenty years. For any chance of staying below the 1.5c limit, seen as an essential target to ensure the survival of earth’s most vulnerable communities and ecosystems, drastic reductions in CO2 would be needed by the end of this decade and net zero emissions met by 2050.
Scientists are now better able to analyse climate impacts at regional levels and understand what global climate impacts will look like in different parts of the world. Climate modelling shows that the Arctic is warming at a faster rate than other regions, and high latitudes in the Northern Hemisphere are projected to heat up by two to four times the level of global warming.
Should a total collapse of the Atlantic Ocean current occur, it would cause havoc on regional weather patterns by weakening African and Asian monsoons and intensifying dry weather in Europe.
The report forewarns about tipping points, a term for the possibility of irreversible changes to the climate. As temperatures rise, forests could start to die, deconstructing earth’s natural lung system, as forests will be less able to absorb carbon dioxide outputs. Antarctic ice sheets could become destabilised, leading to rapid sea level rise. Such melting of these ice sheets could cause sea levels to rise more than a metre by 2100 and 15 metres by 2500.
Despite the bad news, IPCC author Professor Piers Forster from the University of Leeds said he and fellow authors are “really certain” that short term cuts in emissions can “really reduce the rate of unprecedented warming”.