In commemorating World Environment Day under the slogan 'Our Land, Our Future,' we must confront the urgent imperative of safeguarding ecosystems globally to achieve the Sustainable Development Goals. However, the escalating crisis of climate change, particularly the rapid meltdown of glaciers, poses formidable challenges to these aspirations, impacting human communities, biodiversity, and the environment.

NASA's data reveals a stark reality: since 1880, the Earth's average global temperature has surged by at least 1.1°C (1.9°F), with a significant portion of this warming occurring since 1975, accelerating at a rate of roughly 0.20°C per decade. Such a temperature surge carries significant consequences, considering the monumental effort required to elevate the heat content of the oceans, atmosphere, and land masses.

Historically, relatively minor temperature variations have caused profound environmental shifts, such as the Little Ice Age triggered by a mere 1-2°C drop and vast regions of North America encased in ice some 20,000 years ago by a 5°C drop.

The distressing plight of the highest glacier on Mount Everest serves as a poignant illustration of our current predicament. Since the 1990s, this glacier has been melting at an alarming pace, witnessing the disappearance of ice that took approximately 2,000 years to form within mere decades. This distressing phenomenon isn't confined to Everest alone; glaciers worldwide are in retreat, with potentially catastrophic consequences. Millions of people, along with vital biodiversity, rely on the Himalayan mountain range for drinking water and thrive. Should other glaciers follow Everest's lead, their diminished capacity to provide water for drinking and irrigation could severely impact communities and biodiversity. With glaciers serving as custodians of approximately 75% of the Earth's freshwater, their dwindling size alters the water cycle, imperiling over a billion people and vast biodiversity dependent on glacier-fed rivers. Moreover, the melting of glaciers in regions like Antarctica and Greenland contributes to rising sea levels, imperiling coastal communities and ecosystems with erosion and inundation. Similarly, melting of the Himalayan ice may imperil Terai region in Nepal.

Yet, amidst these overt consequences lies a hidden peril: the release of ancient glacier microbes trapped within ice. As glaciers thaw, these microbes infiltrate modern environments, potentially disrupting ecosystems and introducing novel pathogens. While the precise role of microbes in climate systems remains elusive, their ability to produce greenhouse gases such as methane and accelerate glacial melting rates by up to 25% through processes like 'bioalbedo' underscores their significance. Greenhouse gases trap heat in the Earth's atmosphere, causing global warming. Understanding these microbial contributions is imperative for honing climate models and devising effective mitigation strategies.

Recent scientific research affirms the resilience of microbes, revealing their capacity to survive and remain metabolically active in ice for millions of years. Studies conducted in Antarctica's subglacial lakes have unearthed genetic material from bacteria capable of active metabolism, hinting at their persistence in isolation over millennia. Upon release from melting ice, these ancient microbes swiftly 'wake up' and commence metabolic activities, prompting inquiries into the phenomenon of 'genomic recycling' and its ecological ramifications. Additionally, the potential for ancient microbes to introduce novel genes and functions into contemporary microbial communities poses profound implications for ecosystem dynamics, biogeochemical processes, and the emergence of pathogens and pandemics.

Moreover, the melting of glaciers facilitates the dissemination of emerging diseases, imperiling human health and biodiversity. Shifts in precipitation, temperature, and humidity foster the proliferation and dissemination of pathogens, sparking outbreaks of diseases like cholera and cryptosporidiosis. Intense rainfall and flooding mobilize pathogens and toxins, heightening exposure risks, while elevated temperatures incubate pathogens in recreational waters, engendering health hazards. The surge in temperature-induced pathogenic microbes, including Naegleria fowleri referred as 'brain-eating amoeba', opportunistic fungal Candida auris, infectious Salmonella; Campylobacter and Legionella underscores the global public health urgency of proper cooperation in monitoring and managing microbial threats.

As climate change advances, the range of pathogens and their vectors is anticipated to expand, potentially ushering diseases into new territories. For example, the dengue virus, typically confined to tropical areas particularly in Terai regions, has been shifted in cooler hill regions of Nepal. Collaborative global efforts are imperative in monitoring and managing microbial threats, given the emergence of pathogens like Vibrio spp. and cyanobacteria, underlining the urgency of comprehending how environmental changes influence pathogen dynamics to formulate effective public health responses.

Although human activities predominantly drive climate change, microbes also play a pivotal role. As the most abundant organisms on Earth, microbes both shape and affected by a changing climate. Nevertheless, amid these challenges lies a glimmer of hope: microbes have demonstrated remarkable resilience and adaptability throughout Earth's climatic vicissitudes. Microbes, including methanotrophs Gammaproteobacteria, Archaea, are studied as solutions to reduce greenhouse gas emissions. Soil microbes aid crop growth and resilience against environmental stressors like drought and heat waves, critical for food security.

Harnessing microbial processes presents promising avenues for mitigating climate crisis, from curbing greenhouse gas emissions to fostering sustainable energy production through biofuels and microbial fuel cells.

Microbes have thrived on Earth for billions of years, adapting to extreme conditions. As we climate crisis, studying microbes and their interactions in global warming environment offers valuable lessons in resilience and adaptation.

In summary, the melting of Himalayan glaciers and Arctic icebergs, along with the release of ancient microbes, serves as a poignant reminder of the intricate nexus among climate, ecosystems, biodiversity, and human health. It is crucial for the Nepal Government, stakeholders, and the local community to prioritize mitigation strategies to address the climate crisis and preserve biodiversity and the environment. Harnessing the ecological potential of microbes is key to building a sustainable future amid climate crisis, essential for safeguarding entire ecosystems and promoting a healthy livelihood.

Dr. Dulal is a Nepal-based researcher at Nexus Institute of Research and Innovation (NIRI).