thoughts on the latest IPCC climate change report

CAMBRIDGE CITY COUNCIL Quinton Y. Zondervan City Councillor To the Honorable, the City Council: Last week, the Intergovernmental Panel on Climate Change (IPCC), the United Nations agency tasked with tracking climate change, finalized and released its sixth full report on climate change. The previous report came out in 2014 and informed the Paris Climate Agreement of 2015. The new report affirms that global warming will likely exceed 1.5°C this century: “Global GHG emissions in 2030 implied by nationally determined contributions (NDCs) announced by October 2021 make it likely that warming will exceed 1.5°C during the 21st century and make it harder to limit warming below 2°C.” (page 10) Graphic from page 23 showing that to stay below 1.5 degrees, the world will have to make deep and rapid cuts to greenhouse gas emissions starting right now. Currently implemented policies, shown in red, simply won’t get the job done. CITY HALL, CAMBRIDGE, MASSACHUSETTS 02139 Email: qzondervan@cambridgema.gov

I actually attended the December 2015 climate conference (COP 21) that resulted in the Paris Agreement. At the time, the message was that keeping total global warming below 2 degrees Celsius from pre-industrial times (so the increase from average temperatures between 1850–1900) was essential to avoiding catastrophic damages to our civilization, and that if we exceeded 1.5 degrees Celsius, parts of our global civilization, particularly the small island nations, would suffer catastrophic damages so severe that they would not survive (primarily because of sea level rise). The treaty negotiators initially focused only on limiting warming to 2 degrees Celsius, not 1.5. So, I joined climate activists from across the world who marched in protest through the hangars of Le Bourget Airport, chanting: “One point five to stay alive!” We did convince the negotiators to include 1.5 degrees as a stretch goal in the final treaty. But emissions reductions pledges made over the last seven years won’t be enough to keep us below 2 degrees, let alone 1.5. There is some good news in the report, including that renewable energy has now become the cheapest and most cost effective way to generate electricity, giving us a pathway for avoiding catastrophe. Several mitigation options, notably solar energy, wind energy, electrification of urban systems, urban green infrastructure, energy efficiency, demand-side management, improved forest- and crop/grassland management, and reduced food waste and loss, are technically viable, are becoming increasingly cost effective and are generally supported by the public. (page 11) And, there is hope that if we make deep enough cuts fast enough, we can stabilize the climate in about 20 years. “Deep, rapid, and sustained reductions in greenhouse gas emissions would lead to a discernible slowdown in global warming within around two decades, and also to discernible changes in atmospheric composition within a few years.” (page 12) The most positive spin I can put on the report is: if we make drastic reductions in emissions over the next 10 years, we can still avoid 1.5 degrees this century, but we’ve got to get on it, because that window of opportunity is rapidly closing. “All global modelled pathways that limit warming to 1.5°C (>50%) with no or limited overshoot, and those that limit warming to 2°C (>67%), involve rapid and deep and, in most cases, immediate greenhouse gas emissions reductions in all sectors this decade.”). (page 21) It’s important to note, and the report is clear on this, that if we get this right, global average temperatures can decline again this century! We can still save our coastal cities and small island nations, but only if we make a major push for it, starting right now! In service, Quinton Y. Zondervan Cambridge City Councillor 2