The much anticipated global climate science report Climate Change 2021: The Physical Science by Working Group I of the UN’s Intergovernmental Panel on Climate Change (IPCC) has been released. The report brings together the latest advances in climate science, combining multiple lines of evidence from paleoclimate, observations, process understanding, and global and regional climate simulations.
As the first of four contributions to the IPCC’s Sixth Assessment Report (AR6), the report synthesizes understanding of the current state of the climate, including how it is changing and the role of human influence, and the state of knowledge about possible climate futures, climate information relevant to regions and sectors, and limiting human-induced climate change.
With this up-to-date physical understanding of the climate system and climate change, the report finds that increasing global warming is leading to increased frequency and intensity of hot extremes, marine heatwaves and heavy precipitation, agricultural and ecological droughts in some regions, and proportion of intense tropical cyclones, as well as reductions in Arctic sea ice, snow cover and permafrost. The findings result in five key takeaways:
The report highlights that “limiting human-induced global warming to a specific level requires limiting cumulative CO₂ emissions, reaching at least net zero CO₂ emissions, along with strong reductions in other greenhouse gas emissions.”
Professor Nathalie Seddon, NbSI director, states: “What is very clear is the urgent need to slash emissions. If we do not, then continued warming will undermine the capacity of ecosystems to sequester and store carbon, leading to their conversion to net sources rather than net sinks of greenhouse gases. It is also vital that pathways to achieving net zero, whether through technological or nature-based approaches, do not compromise nature recovery and support biodiversity conservation and other societal challenges.”
NbSI Senior Associate Alison Smith notes: “The stark warnings of this report emphasise that we need to accelerate decarbonization at rates never achieved before, almost eliminating fossil fuel use, and cutting our over-consumption of energy and materials to sustainable levels. It is also essential to protect the vast amounts of carbon stored in ecosystems such as native forests, fens, peatlands, ancient grasslands and marine sediments.”
“Even if we accelerate decarbonization at rates never achieved before, only reducing emissions is not sufficient to achieve net zero. It is also necessary to actively remove and store carbon dioxide from the atmosphere through Negative Emissions Technologies (NETs). This includes removing carbon from the atmosphere via carefully designed, ecologically sound and socially equitable nature-based solutions that restore degraded ecosystems and ensure the sustainable management of working lands. However, other NET options such as Bioenergy with Carbon Capture and Storage (BECCS) should be used with caution: they use vast areas of land, and do not provide the multiple long-term benefits of nature-based solutions, often compromising food security and biodiversity,” adds Dr Cécile Girardin, NbSI Technical Director.
Transformative change is needed to reduce and remove emissions (mitigation), and address their impacts (adaptation). Such action should not rely solely on technological innovations, but also innovation in nature-based solutions and governance that will play key roles in reducing, mitigating and adapting to climate change.Tweet