It’s becoming more evident that achieving our climate objectives is slipping away. By 2022, we had already experienced a warming of 1.26°C, and if current trends persist, we’re set to surpass the 1.5°C mark by the mid-2030s. Disturbingly, recent studies indicate that the existing climate policies are steering us towards a temperature increase exceeding 2.5°C by the close of this century.
The substantial warming predicted poses a serious threat to communities and ecosystems worldwide, especially those already vulnerable. It’s high time we explore innovative approaches that could effectively halt the progression of climate change.
Following impactful volcanic eruptions such as Tambora in 1815 (Indonesia) and Pinatubo in 1991 (Philippines), there’s a temporary dip in global temperatures. These significant eruptions generate a hazy layer of tiny particles in the upper atmosphere, persisting for several years and causing a temporary dimming of the Sun. Mimicking this phenomenon could be a potential strategy to combat climate change.
The Sun provides warmth to the Earth, yet it’s the greenhouse gases retaining the heat emitted by our planet that sustain this warmth. The warming impact of our carbon dioxide emissions might be offset by introducing a lasting, man-made haze akin to the aftermath of significant volcanic eruptions. Studies indicate that dimming the Sun by approximately 1% could result in a cooling effect, reducing the planet’s temperature by 1°C.
While it may seem improbable, all engineering evaluations conducted so far have affirmed the feasibility and cost-effectiveness of the idea. The proposed method involves deploying a fleet of high-altitude jets to disperse reflective particles into the upper atmosphere, effectively dimming the Sun. The question that remains is not whether we can do it, but whether we should.
Cooling the planet would work
While dimming the Sun wouldn’t completely undo climate change, it’s essential to acknowledge the nuances. The Sun’s impact is most pronounced during daytime, in summer, and at the Tropics, whereas greenhouse gases contribute to warming universally and continuously.
Nevertheless, a strategic adjustment in the release of reflective particles could generate a more uniform cooling effect worldwide. Recent research indicates that adopting such an approach has the potential to significantly diminish climate-related risks.
The significance of escalating temperatures cannot be overstated. Species globally are adjusting their habitats, migrating towards cooler climates as the Earth experiences warming trends. Unfortunately, not all species can adapt swiftly to these climate shifts, and some face the dire situation of having no suitable alternative habitats. As a result, projections indicate a rise in the number of extinctions due to these changing climate conditions.
Additionally, we’re witnessing intense heat approaching the absolute thresholds of the human body, jeopardizing lives and constraining outdoor activities.
With the planet experiencing a rise in temperatures, the warmer air is now extracting increased moisture from the soil during dry periods and releasing it in more substantial amounts during rainfall. This phenomenon is causing arid areas to become even drier, while simultaneously amplifying precipitation in already wet regions. The consequence is a heightening of both droughts and floods on a global scale.
Implementing solar dimming would indeed counteract this phenomenon. However, it comes with its own set of consequences, particularly in altering the global wind and rainfall patterns.
Studies suggest that the overall impact of rainfall changes would be relatively modest. Yet, certain locations might experience more pronounced alterations compared to the shifts anticipated from climate change alone. The specifics of regional rainfall changes remain uncertain, as climate models diverge on this aspect.
Employing sunlight blocking, as outlined in recent research, proves effective in preserving icy regions globally. The accelerated melting of Antarctic and Greenland ice sheets, attributed to rising temperatures, is a significant contributor to the escalation of global sea levels. Additionally, climate change-induced thawing of permafrost, a frozen soil reservoir containing substantial carbon, is releasing increased amounts of methane and CO₂, as highlighted in this research.
Side effects
While dimming the Sun could regulate Earth’s temperature, it wouldn’t address the core issue of climate change: the accumulation of CO₂ and other greenhouse gases in the atmosphere. Beyond its role in warming the planet, CO₂ also plays a part in acidifying the ocean, posing challenges for the formation of shells in corals and other marine organisms. It’s crucial to recognize that dimming the Sun wouldn’t mitigate this aspect of the problem.
Introducing a hazy layer of particles, as suggested in research, would indeed have some side effects. This particle-infused atmosphere could contribute to making the sky somewhat whiter. Following the model of volcanic eruptions by releasing sulfate particles into the upper atmosphere might exacerbate the acid rain issue.
Furthermore, there’s a potential impact on the ozone layer, crucial for shielding us from harmful UV rays. Research suggests that introducing more sulfate particles into the upper atmosphere could delay the gradual recovery of the ozone hole.
Acknowledging these concerns, it’s essential to note that they are outweighed by the potential benefits of reducing extreme heat. A recent study indicates that the positive impact on human health, stemming from decreased extreme heat, could surpass the health-related consequences of these side effects by more than 50 to 1.
Paul Crutzen, Nobel laureate in 1995 for his work on the ozone hole, recognized these side effects. Despite acknowledging the importance of swiftly reducing CO₂ emissions, he stressed the need to seriously consider the idea of dimming the Sun. In a 2006 article, he emphasized that the best scenario would be rapid CO₂ emission cuts, rendering solar dimming unnecessary. However, he lamented that achieving this seemed like an idealistic hope at the time.
Symptoms matter
It’s becoming increasingly evident that the “pious wish” expressed by Crutzen in 2006 remains unrealized. Since his article, CO₂ emissions have surged by over 15%, underscoring our failure to slash emissions rapidly enough to avert severe damage from climate change.
While dimming the Sun doesn’t address the fundamental cause of the climate predicament, the emerging body of evidence suggests it could remarkably alleviate the symptoms. This isn’t entirely surprising; ice melts in warmth, heightened air temperature carries more moisture, and heat directly impacts life. While we’re not currently equipped with enough knowledge to outright endorse solar dimming, the growing urgency demands serious consideration. Failing to take this idea seriously could mean missing a valuable opportunity to mitigate the risks of climate change.
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