Critical Climate Warning
In a recent study conducted by researchers from Imperial College London, they issued a grave warning: the Earth faces a 50% likelihood of experiencing a substantial 1.5°C temperature increase before 2030 if we do not promptly reduce carbon dioxide emissions.
Published in the journal Nature Climate Change, this study presents the most current and comprehensive analysis of the global carbon budget, which estimates the allowable carbon dioxide emissions to remain within specific temperature limits.
The global community, through the Paris Agreement, has committed to limiting global temperature increases to below 2°C above preindustrial levels and striving to keep it within 1.5°C. The remaining carbon budget serves as a crucial benchmark for assessing progress towards these goals.
The study’s findings are unsettling. To maintain a 50% chance of limiting temperature rise to 1.5°C, we are left with less than 250 gigatonnes of carbon dioxide in the global carbon budget. This implies that if carbon emissions continue at 2022 levels, approximately 40 gigatonnes per year, we will deplete the budget by around 2029. Consequently, we will be locked into a 1.5°C warming scenario compared to preindustrial levels. This alarming decline in the carbon budget has transpired since 2020, primarily due to the ongoing increase in global greenhouse gas emissions, mainly from fossil fuel combustion, and a more precise estimate of aerosols’ cooling effects. These aerosols are diminishing globally due to measures aimed at enhancing air quality and reducing emissions.
Dr. Robin Lamboll, a research fellow at the Centre for Environmental Policy at Imperial College London and the study’s lead author, emphasizes the urgency of the situation. He points out that the remaining budget is now so small that minor changes in our understanding of the world can result in significant proportional changes to the budget. Estimates suggest that we have less than a decade of emissions at current levels. The lack of progress on emissions reduction means that the window for keeping warming at safe levels is rapidly closing.
Dr. Joeri Rogelj, Director of Research at the Grantham Institute and Professor of Climate Science and policy at the Centre for Environmental Policy at Imperial College London, echoes the study’s findings and their alignment with the latest UN Climate Report. He highlights the importance of considering the uncertainty surrounding central estimates.
In addition to the alarming carbon budget for 1.5°C, the study also unveils that the carbon budget for a 50% chance of capping warming at 2°C is around 1,200 gigatonnes. This means that if carbon emissions persist at their current levels, we will deplete the central 2°C budget by 2046. Previous attempts to calculate the remaining carbon budget have been complicated by various factors, including the warming effects of gases other than carbon dioxide and the persistent impacts of unaccounted emissions.
This research distinguishes itself by utilizing an updated dataset and improved climate modeling, shedding light on the uncertainties surrounding the remaining carbon budget estimates and offering insights into how the climate system may respond as we approach net-zero emissions.
The concept of “net zero” refers to achieving an equilibrium between global emissions and emissions removed from the atmosphere. The study underscores the significant uncertainties that exist concerning how different aspects of the climate system will behave in the years leading up to net zero. It is plausible that the climate may continue warming due to factors such as melting ice, methane release, and changes in ocean circulation. Conversely, increased vegetation growth, acting as carbon sinks, could absorb substantial amounts of carbon dioxide, leading to a cooling effect before reaching net zero.
Dr. Lamboll stresses the urgency of cutting emissions, emphasizing that every fraction of a degree of warming will make life harder for people and ecosystems. This study serves as yet another warning from the scientific community, and it is now up to governments to take decisive action. The time to act is now, and it is imperative that we address this crisis before it exacerbates further.