Dhanada K. Mishra, Hong Kong, 8 May 2023
The Intergovernmental Panel on Climate Change, or IPCC, has recently released its final report called the AR6 Synthesis Report. Its a culmination of a process in which several reports were published in earlier years on various aspects of climate change, which have been synthesised in the final report. IPCC reports draw together a consensus from the existing relevant scientific literature. And the agreement is that “human activities have unequivocally caused global warming of 1.1°C due to unsustainable energy use, land use, lifestyles, and consumption.”
Will Arnold, a structural engineer from the UK and Head of Climate Action at the Institution of Structural Engineers, recently produced a summary of the IPCC’s latest report. Here, I will share his views on what the report calls for, and how it applies to the built environment.
Total emissions for 2019 stood just short of 60 billion tonnes of CO2eqv, and atmospheric CO2 concentrations are higher than at any time in at least 2 million years. Responsibility for this mess is unequal: the dirtiest 10% of households have been responsible for 40% of these emissions. That is the global North responsible for most of the mess.
The impacts of such warming are being felt worldwide: measured increases in human mortality and morbidity due to extreme heat events and increases in climate-related food-borne, water-borne, and vector-borne diseases.
With the most vulnerable communities being affected most by the impacts of climate breakdown, inequality is glaring. A third of the global population lives in contexts highly susceptible to climate change, despite contributing to less than 10% of global emissions. In the world’s most vulnerable regions, human mortality due to recent flooding, droughts and storms was 15x higher than in the more resilient areas.
Emissions and heating are intimately connected. Halving emissions by 2030 and reaching Net Zero by 2050 would limit the temperature increase to 1.5°, but delaying this till 2070 increases this to 2°. Going further, if we are still emitting at today’s levels by 2050, we will hit 3°, and if emissions double by that year, we will exceed 4°. It is quite a range, indeed!
One of the few good news in the report is that regulations passed so far are expected to have reduced yearly emissions by about 10% compared to how bad they could have been. But overall, our year-on-year emissions continue to climb, and the “halving by 2030” target is unlikely to be met.
Emissions predictions for 2030 based on countries’ nationally determined contributions (NDCs; the pledges last updated at COP26) are unlikely to put us below 2° – and so far, there has been insufficient policy change or finance even to meet these.
Due to sea level rise (at least 20cm by 2050), current 1-in-100-year extreme sea level events are projected to occur annually by 2100 in more than half of all tide-gauge locations worldwide.
1 Based on summary by Er Will Arnold (https://www.linkedin.com/in/willarnoldengineer/)
In the near term, the world will experience an increase in climate hazards, including droughts, storms, flooding, disease, biodiversity loss (on land and in water), and a decrease in food production in those places most of the world currently relies on. We are already experiencing all this as we jump from drought to storms to heat waves to flooding within a year.
The thin silver lining is that there are solutions to all of this. The IPCC are clear about how quickly humanity could turn this around if world leaders chose to act sufficiently. “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.”
We are still in progress, but we have all the technical knowledge and the global capital to do so. The bigger question is whether we have the political leadership and the societal support to enable this. The report argues for reducing emissions by coordinating action across value chains to promote multiple mitigation options. It calls for circular material flows, increased energy and materials efficiencies, and transformational changes in production processes.
The built environment is cited as requiring systematic change, referencing walkable cities with robust public transportation and active mobility options, filled with reused and efficiently designed buildings. Finally, the report calls for a just transition through these systematic changes – highlighting the need to prioritise equity, climate justice and inclusion. It highlights how prioritising these can enable adaption and resilience and will support the most ambitious mitigation actions.
The IPCC clearly states this is a critical time for humanity, stating that “the choices and actions implemented in this decade will have impacts now and for thousands of years”. Whatever change you have experienced so far is not enough. So how do we create a rapid paradigm shift in construction? We know that our primary palette of construction materials will not decarbonise at the rate required to achieve 1.5°. So the way we design must fundamentally change.
We must transition towards a circular economy, prioritising retrofit over new-build and finding ways to reclaim and reuse materials and products rather than recycling them. We must strengthen and adapt existing buildings, enable vertical extensions, and unlock forgotten inner-city sites. Where new facilities are essential, we need to design far more efficiently and allow the use of lower-carbon materials and products.
“Er Arnold believes that the most rapid shift in the built environment will come from society becoming more selective about what is built – learning that some construction is needed more than others. We should build things that benefit the community and nature, not just provide a return on investment.
We need regenerative buildings with multiple uses that cause nature to thrive and society to re-energise. If industry leaders can champion this and share their newfound knowledge on an open-source basis, the tides may turn.
Human ingenuity is one resource that is not in short supply. Humanity’s biggest hope is that it has risen to the occasion and found a solution when challenged. It is one such existential moment for humanity; only the future will tell if we can overcome it.
