It's official. It's our fault. According to an IPCC report released earlier this month, humans are 'unequivocally' responsible for rising global temperatures. The report states that 245 global experts and 195 governments are in agreement: Human activity is accelerating the warming of our planet. It's not the only release of an IPCC report, either. Draft sections of another report, due for release in early 2022, were leaked back in July. Some of the authors were allegedly concerned that policymakers might try watering down the findings and recommendations ahead of final approval. We now have two important reports: one official and one unofficial release. But what do they mean for our understanding of climate change? And what picture do they paint for the future of us and our planet?
Who is the IPCC and What is The Report?
Each report builds on the last. Scientists now have more available information and their evidence-gathering tools are more advanced. There's a clear evolution in both the language and the understanding of what global temperature rises mean for the future.
Published in the early 1990s, the first report said the link between humans and climate change was 'unproven'. The IPPC's 2013 report declared that the link was 'clear'. This latest report says that humans are 'unequivocally' responsible for climate change. That's quite the journey: unproven to unequivocal in three decades.
245 authors and co-authors helped write the study that examined 14,000 scientific papers. 195 governments also approved the final 3000-page document. There's also a 30-page policymaker's summary available online to read and download.
Website The Conversation has also written about the authors behind the report. All are global experts in their field, and the peer-review process for each section was exhaustive and far more so than what's typically required for scientific publication. Representatives from each government were also required to approve every word contained in the report before it was published. This was so that there would be no disagreement later. It's what makes this report so important.
What does the IPCC Report Say?
The Narwhal website writes that it's the first time scientists and governments from 'around the world have agreed that there is no doubt who is responsible for the climate crisis.' We are. The report also dismisses claims that the planet is warming through natural causes. Humans are responsible for the global 1.2 degree temperature rise. Natural causes caused a rise of only 0.05 degrees. United Nations secretary-general António Guterres called the report "a code red for humanity". Here are some of the key takeaways.
- The increased mix of greenhouse gases since 1750 are 'unequivocally caused by human activities'
- Atmospheric CO2 levels are higher now than at any point in the last 2 million years.
- The global surface temperature was 1.09 Celsius higher in 2011 - 2020 than 1850 - 1900.
- The last 4-decades have been warmer than any decade before 1850.
- "It is unequivocal that human influence has warmed the atmosphere, ocean and land. Widespread and rapid changes in the atmosphere, ocean, cryosphere and biosphere have occurred."
- It's 'extremely likely' that human influence is the main driver of ocean warming.
- It's 'virtually certain' that 'hot extremes' have become more frequent and intense since the 1950s. Cold extremes less so.
- It's very likely that human activity has contributed to the surface melting of the Greenland Ice sheet. However, there was limited evidence and 'medium agreement' of human activity causing Antarctic ice sheet loss. Human influence is very likely behind the decline in arctic sea ice.
- Glacial retreat since the 1950s is unprecedented in at least 2000 years.
5 Potential Scenarios
Scenario 1 - if the world remains below a 1.5 degrees temperature growth, then extreme weather will be more common but the worse effects of climate change will be avoided. This was the target set by the 2015 Paris Agreement.
Scenario 2 - if the world reaches net-zero after 2050, the temperatures will stabilise at around 1.8 degrees by the century's end.
These are best-case scenarios. Although, it looks very unlikely that scenario 1 will be possible.
Worst-case scenarios 4 and 5 can be summed up by an article in the Guardian "If emissions do not fall in the next couple of decades, then 3C of heating looks likely - a catastrophe. And if they don't fall at all, the report says, then we are on track for 4C to 5C, which is apocalypse territory." Apocalypse territory. That's pretty terrifying. But it's not all doom and gloom. New Scientist writes how it's a lot to process. Tamsin Edwards from Kings College London was one of the report's lead writers. She believes people need to come to terms with the fact that humans have caused irreversible damage to the planet. But she also believes that there's 'still hope'. And the report makes strong suggestions about what needs to be done. It argues for net-zero carbon emissions at the very least. It also calls for a "very strong reduction of methane emissions". Methane is the second-largest contributor to greenhouse emissions after C02. Carbon Brief explains that it's 84 to 86 times stronger than CO2. The five scenarios outlined by the IPCC also show that we don't have to accept an apocalyptic climate catastrophe. It is possible to limit the effects of climate change. Governments have to set the standard but we must all take responsibility. Anyone can live an eco-friendlier lifestyle. If you have children or grandchildren, this should be especially important. According to the IPCC's findings, disaster is not as far into the future as you may think. They're talking decades, not centuries.
The Leaked Document
The IPCC is currently working on a third part of the report due for release in 2022. In June 2021, a draft version of the document was leaked to the Spanish press. Some of the authors involved were allegedly concerned that it could be watered-down to become more palatable for policymakers. They wanted the public and media to see the original recommendations. The leaked document does tell us some interesting things. It says that greenhouse emissions must peak globally before 2025. And that between 2050 and 2075, C02 emissions must be net-zero. It advises a ban on building new fossil fuel or gas plants and that all existing plants must close within the next ten years. The report acknowledges that richer nations emit more greenhouse gasses than poorer nations. The rich are 'in every country…overwhelmingly more responsible for global heating'. And Yahoo reported on the impact the leaked document says we're likely to see in countries across the Mediterranean. "Reasons for concern include sea-level rise related risks, land and marine biodiversity losses, risks related to drought, wildfire, alterations of water cycle, endangered food production, health risks in both urban and rural settlements from heat, and altered disease vectors," More than half a billion people live in the Mediterranean region. The IPCC believes that the area faces "highly interconnected climate risks".
The report also talks about tipping points. This is where one event goes on to trigger another catastrophic event. For example, the rise in global temperature now means there's less ice in the Arctic during the summer. Within a couple of decades, there'll be no ice there at all during the warmer months. This means there's nothing to reflect sunlight away from the earth and back into space. Without the ice, the light will go into the water warming it up even more. This will exacerbate further ice loss and lead to higher sea levels. The Guardian expands on these tipping points. Higher temperatures will also mean a melting of the Arctic permafrost. This will lead to the release of methane which will contribute to global heating. Melting the polar ice sheets brings will bring about inevitable catastrophic sea level rises. Isolating one climate disaster from another may well prove to be impossible. It's another reason why the IPCC report urges fast action.
The IPCC report gives us the definitive answer. Humans are responsible for rising global temperatures. It also gives us the responsibility for fixing things. And for what we can't fix, the responsibility of minimising the permanent changes we've made to our planet. It will be interesting to see what role the report plays at COP26 in Glasgow later this year.