In a startling revelation, research led by James Hansen, the renowned US scientist who initially alerted the world to the greenhouse effect, suggests that global heating is advancing at a more rapid pace than previously understood. This acceleration could lead to a pivotal temperature threshold being surpassed as early as this decade.
The research unveils an alarming reality: the Earth’s climate is far more sensitive to human-induced changes than previously acknowledged. This heightened sensitivity implies that the world will soon experience a “dangerous” surge in global heating. The study predicts that global temperatures will increase by 1.5 degrees Celsius over pre-industrial levels in the 2020s and rise by 2 degrees Celsius by 2050. Such an accelerated progression towards extreme heating jeopardizes a world “less hospitable for humanity and fraught with increased climate extremes.”
James Hansen, a former NASA scientist and pivotal figure who testified before the US Congress on climate change back in the 1980s, underlines the profound consequences of this alarming revelation. He emphasizes that there is an extensive “pipeline” of global heating consequences due to continued fossil fuel consumption. Earth’s sensitivity to these impacts significantly surpasses estimates provided by the United Nations’ Intergovernmental Panel on Climate Change (IPCC). In his words, “We must be prepared for an acceleration of global warming, and this is the onset of reaping the consequences of our choices.”
The topic of whether global heating is accelerating has sparked fervent debates within the scientific community, particularly in the face of record-breaking temperatures witnessed over the past year.
Hansen underscores a significant imbalance between the energy received from the sun and the outgoing energy from the Earth. This discrepancy has “noticeably expanded,” almost doubling over the last decade. The ramifications of this escalation could potentially lead to catastrophic sea-level rise for coastal cities around the world.
This newly released research, authored by Hansen and more than a dozen other scientists, contends that this energy imbalance, along with the Earth’s heightened climate sensitivity and a reduction in pollution stemming from shipping activity (which has reduced airborne sulfur particles that reflect incoming sunlight), is propelling global heating to new extremes.
The research paper raises an alarm, stating, “We find ourselves in the early stages of a climate emergency, and this acceleration is perilous in a climate system that is already severely unbalanced. Rectifying this trend is imperative for the preservation of coastlines and the safety of the world’s coastal cities.”
To address this imminent crisis, Hansen and his peers advocate for a global carbon tax, along with a more controversial proposal to intentionally introduce sulfur into the atmosphere to deflect heat from the Earth’s surface. This approach, known as “solar geoengineering,” has faced criticism due to potential environmental consequences and the risk of rapid heating should sulfur injections cease. Nevertheless, a minority of scientists favor this approach, emphasizing the world’s dwindling time and limited alternatives to avert catastrophic temperature increases.
Hansen clarifies that while reducing emissions remains the highest priority, “owing to the slow progress in developing carbon-free energy sources and the failure to impose carbon emission fees, it seems unlikely that we can attain a brighter future for our younger generations without temporary aid from solar radiation management.”
This year is well on course to become the hottest year ever reliably recorded. Record temperatures observed in September were described as “extraordinarily abnormal” by climate researchers. A recent report highlights that the carbon budget required to limit global heating to 1.5 degrees Celsius is nearly depleted due to ongoing fossil fuel combustion and deforestation.
Although scientists concur on the overarching trend of increasing global heating, the consensus regarding the acceleration of this trend remains inconclusive.
Michael Mann, a climate scientist at the University of Pennsylvania, states that Hansen and his co-authors occupy a position “outside the mainstream” by asserting a consistent acceleration in surface heating that has been relatively steady for decades. Mann contends that reductions in shipping emissions have only a marginal influence on the climate system and asserts that advocating for solar geoengineering is misguided and “a slippery slope.”
Bärbel Hönisch, a paleoclimatologist at Columbia University, acknowledges some reservations regarding the certainties outlined in Hansen’s research about the Earth’s climate conditions millions of years ago, which help predict the effects of current warming. She offers a tempered perspective: “I maintain some reservations, but they might well be correct. This paper raises significant questions that will prompt extensive research to deepen our understanding.”
Several other researchers express less skepticism toward Hansen’s dire warning of an escalated global heating crisis, appreciating his prior warnings on the climate crisis. Hansen’s longstanding warnings have largely materialized due to decades of inaction in mitigating fossil fuel usage. Rob Jackson, a scientist at Stanford University and chair of the Global Carbon Project, supports Hansen’s contention that the IPCC may have underestimated climate sensitivity. He notes, “It’s challenging to discern what is improbable anymore in terms of heating. There hasn’t been a global decline in fossil fuel consumption, not even for coal. I believe Hansen’s pessimism is justified. He sounded the alarm 35 years ago, and the world mostly disregarded him – and all of us.”