Food Security

Our Double-Edged Nitrogen Sword Nitrogen exists as a profound duality in Earth’s systems. Its inert atmospheric form ($N_2$) constitutes the most abundant gas surrounding the planet, serving as an invisible backdrop to existence. When converted into reactive forms through fixation processes, nitrogen transforms into a fundamental building block for proteins and DNA, becoming the engine of agricultural productivity that sustains billions of people. ...

Historical Evolution of Water Security Understanding The understanding of water security has evolved significantly over time, particularly in conjunction with the growing awareness of climate change. Historically, water management often focused on ensuring supply for specific sectors like agriculture or urban consumption, often through large-scale infrastructure projects such as dams and irrigation systems1. However, the late 20th and early 21st centuries saw a broadening of the concept of “water security” to encompass not just quantity but also quality, ecosystem health, and the equitable distribution of water resources23. ...

A Planetary Problem with a Social Toll Ocean acidification, driven by anthropogenic carbon dioxide emissions, represents a critical planetary boundary within Kate Raworth’s Doughnut Economics framework, directly linking climate change impacts to marine ecosystem health and human food security. As atmospheric CO₂ levels have risen from pre-industrial concentrations of 280 µatm to current levels exceeding 414 µatm, the ocean’s absorption of this excess carbon has fundamentally altered seawater chemistry1. This process has decreased ocean pH by approximately 0.1 units since the Industrial Revolution, with projections indicating further declines to pH 7.8 by 2100 and potentially as low as 7.45 by 23002. The concept of fish adaptation to ocean acidification sits at the intersection of planetary health and social foundations, as marine fisheries provide essential protein sources for over 3 billion people globally while supporting the livelihoods of millions in coastal communities. ...

Understanding Stratospheric Ozone and Its Vulnerability The stratospheric ozone layer, situated approximately 12 to 30 miles above Earth’s surface, plays a crucial protective role by absorbing harmful ultraviolet (UV) radiation from the sun12. This atmospheric shield prevents dangerous levels of UV radiation from reaching Earth’s surface, where it would otherwise cause significant harm to humans, wildlife, and ecosystems34. Under natural conditions, ozone ($O_3$) undergoes a continuous cycle of formation and breakdown, maintaining a dynamic equilibrium. In this cycle, ozone absorbs UV radiation and breaks down ($O_3$ + UV light $\rightarrow$ O + $O_2$), but the resulting oxygen atoms can recombine to reform ozone, thus preserving the protective layer while absorbing harmful radiation56. This delicate balance, dependent on complex atmospheric chemistry, evolved over billions of years, creating conditions conducive to life on Earth’s surface42. ...

A (Grim) History of Hollowing Out Our Home The understanding of biodiversity as a planetary boundary has developed considerably over recent decades. Scientists have progressively recognized that biological diversity represents not merely an environmental concern but a fundamental limit to human activities. This recognition began with the Stockholm Resilience Centre’s introduction of the planetary boundaries framework, which identified biodiversity (or biosphere integrity) as one of nine critical Earth system processes that maintain planetary stability1. ...