Is IPCC still relevant for climate policy?

Ahead of #COP28, read our article on why IPCC's climate scenarios are pivotal for understanding and responding to climate change and how over time, these scenarios have become more complex, reflecting improved climate modelling and comprehension. Scenarios guide policymakers by outlining potential climate impacts and risks under different emissions trajectories. They also provide key data for quantifying climate impacts and guiding adaptation strategies globally and locally. However, frequent terminology changes across IPCC assessment cycles have caused confusion and challenges for governments and stakeholders using the scenarios, with estimated transition costs of USD 200 million. To ensure clarity going forward, the IPCC should maintain consistent scenario vocabulary from the 6th Assessment Report through at least the 7th, and potentially in future assessment cycles. Full article here https://lnkd.in/g99p2F8J Green Climate Fund, IRDR, International Science Council, CODATA, #CODATA-TG-FAIRdataforDRR; #ClimateAction #GlobalWarming #Environment #Sustainability

Climate models rely on weak data for durable #CarbonRemoval, yet these same models shape today’s climate policy Most climate policy experts tend to focus on the #NDCs as the fundamental tool for creating political buy-in to scale up durable removals. But what informs the NDCs? The #IPCC reports. What informs the IPCC reports? The Integrated Assessment Models (IAMs). The IPCC’s Sixth Assessment Report (AR6) illustrates the problem well. Of the 121 model runs in AR6 scenarios aligned with “well below 2°C” and “above 1.5°C” pathways: 120 deployed BECCS, 28 (!) deployed DACCS None (!) represented biochar or ERW. Carbon Direct has just published an in-depth analysis of the problem and potential solutions. The narrow scope of novel and durable carbon removals in IAMs also shapes many countries' NDCs and long-term strategies. I'd add that there is another important element - the IPCC guidelines for the national greenhouse gas inventories (the GHG accounting rules for the governments), which have also suffered from the same shortcomings. It's great to learn that Carbon Direct is collaborating with three leading research institutions with well-established IAMs: Pacific Northwest National Laboratory, Utrecht University, and the International Institute for Applied Systems Analysis, to close this gap and represent removals more accurately in climate modelling: updating the latest cost assumptions, learning curves, and growth constraints for existing carbon removal technologies, while adding new representations of DACCS, biochar, and ERW. Have a look at their short blog post laying out the key issues: https://lnkd.in/eEczTaW2 There's a link to a longer white paper at the end of the blog. It's well worth the read!

My IPCC journal - Is an IPCC WGI Report (Physical Science) still needed today? Two years ago, as I was candidate for being elected WGI co-chair, I was not convinced, in fact. Do governments need more physical understanding to develop transitions? Not really. Everything was in previous reports. What is needed is trust in well-being 🏖️ under a low-carbon future, in equity across the world for this transition, and effective cooperation to make it happen. Physical Science would likely not help for that. However I accepted the nomination from my government with the hope I was wrong to think WGI could not be useful 🤔. This week, thanks 🙏 to the invitations of the Grantham Research Institute on Climate Change & the Environment, and of the World Climate Research Programme (WCRP), I presented twice the scientific challenges ahead for the 7th cycle for WGI. An opportunity to collect the reasons why the physical science community and the IPCC authors will indeed produce a Report that can be instrumental, at the time of its release (in 2028, if things go well). In the past two years, I became convinced that not only physical climate science will deliver very novel powerful messages, but also WGI can largerly widen its reach through improved communication. This should broaden the motivation for the transition and the trust. That is the bet. 📈 Global warming is now going at full speed, and we see it unfolding, bringing loads of new key observations. ⚡ Are the anomalies and outstanding extremes that we are observing at regional or global scale in proportion of the current global warming level, and what can we expect from these observations for larger warming levels? Observations 🌡️ from the last decade, added to those from previous decades and paleo records will help understand current biases in climate models better than ever. They will help better reduce the uncertainties in future projections, thanks to recently developed statistical methods (eg. Bayesian approaches 🤗). Future realistic emission scenarios 🏭 themselves will learn from recent periods and should span a more reduced spectrum than before. Physics has progressed on various feedbacks in the Earth system (land/atmosphere, clouds, carbon cycle coupled with the water cycle, etc...), and will bring loads of new information on future conditions. How possible is a decrease of global temperatures ❄️ if we go too high, using carbon dioxide removal techniques? What are the critical thresholds at which large-scale reorganizations take place, in the ocean, the atmosphere or in large ecosystems, triggering risks at unprecedented level? 📚 And finally how is climate information used for various audiences, from decision makers in the public or private sectors, to NGOs, teachers, what are the disparities in climate information? 📢 A successful WGI Report willl rely on research published or accepted on those topics (and all those I forgot 😅) by about the end of 2027. Sunrise...