Nepal has approximately 1000 operational brick kilns, which contribute significantly to ambient air pollution. They also account for 1.81% of the total bricks produced in the South Asian region. Little is known about their emissions, which are consequently not represented in regional/global emission inventories. This study compared emissions from seven brick kilns. Four were Fixed Chimney Bull’s Trench Kilns (FCBTKs) and three were Induced-Draught Zigzag Kilns (IDZKs). The concentrations of carbon dioxide (CO₂), sulfur dioxide (SO₂), black carbon (BC), and particulate matter (PM) with a diameter less than 2.5 µm (PM_2.5) were measured. The respective emission factors (EFs) were estimated using the carbon mass balance method. The average fuel-based EF for CO₂, SO₂, PM_2.5, and BC were estimated as 1633 ± 134, 22 ± 22, 3.8 ± 2.6 and 0.6 ± 0.2 g per kg, respectively, for all FCBTKs. Those for IDZKs were 1981 ± 232, 24 ± 22, 3.1 ± 1, and 0.4 ± 0.2 g per kg, respectively. Overall, the study found that converting the technology from straight-line kilns to zigzag kilns can reduce PM_2.5 emissions by ~20% and BC emissions by ~30%, based on emission factor estimates of per kilogram of fuel. While considering per kilogram of fired brick, emission reductions were approximately 40% for PM_2.5 and 55% for BC, but this definitely depends on proper stacking and firing procedures.

Climate solutions related to mitigation and adaptation vary across the United States and India, given their unique current socio-political–technological abilities and their histories. Here, we discuss results from online face-to-face interviews undertaken with 33 U.S.-based climate experts and 30 India-based climate experts. Using qualitative grounded theory, we explore open-ended responses to questions related to mitigation and adaptation and find the following: (1) there is broad agreement among experts in both countries on the main mitigation solutions focused on the decarbonization of energy systems, but (2) there are a diversity of views between experts on what to prioritize and how to achieve it. Similarly, there is substantial agreement that adaptation solutions are needed to address agriculture, water management, and infrastructure, but there is a wide variety of perspectives on other priorities and how best to proceed. Experts across both countries generally perceived mitigation as needing national policies to succeed, while adaptation is perceived as more local and challenging given the larger number of stakeholders involved in planning and implementation. Our findings indicate that experts agree on the goals of decarbonization, but there was no consensus on how best to accomplish implementation.

Given the enormous span of potential strategies to address climate change, it is difficult to build consensus on what to prioritize. In 2021, we conducted 63 semi-structured interviews with climate change experts in the U.S. (N = 33) and India (N = 30). Experts indicated how they would address climate change through mitigation, adaptation, carbon dioxide removal (CDR), and solar geoengineering (SG). Our experts studied climate change from a variety of disciplines and were not necessarily subject matter experts in CDR or SG. Most experts stated that while more research is needed on CDR and SG, there is low appeal to deploying them in responding to climate change. Across our entire sample, we find that 44% of experts supported deploying CDR compared to 3% for SG. We also find that 17% of experts opposed the deployment of CDR, while twice as many (35%) opposed deploying SG. While there is far more support for traditional measures like mitigation and adaptation, most experts were hesitant to support technologies like CDR and SG to limit warming to 1.5 °C or 2 °C to prevent dangerous climate impacts, with statements tending toward a precautionary principle. Deep interdisciplinary engagement by climate change experts on CDR and SG is essential to understanding these technologies’ potential roles in addressing climate change and the perceptions of risk of these technologies held by experts who work on other areas of the climate problem. We highlight the potential for follow-up studies on broader expert opinions of CDR and SG, as well as evaluating whether perceptions and opinions are lagging behind fast-changing developments in the field.