Life is a race of survival within the environment, where every species depends on others through complex ecological interdependence. Yet, human civilisation has increasingly reshaped natural systems for comfort and progress, often disrupting the balance that sustains biodiversity, climate, and health. Urbanisation and industrial growth create artificial ecosystems that consume vast resources and emit pollutants back into the environment.

This study examines how human development can maintain full living standards while reducing environmental imbalance. It focuses on the carbon and nitrogen cycles as indicators of ecosystem stability and evaluates how urban design affects these fluxes.

A model city (“Flux City”) was developed to simulate a fully supplied urban environment with 100% provision of food, water, power, housing, and waste services. Changes in carbon and nitrogen fluxes were analysed against natural baseline values to quantify human impact. Supporting examples from deforestation in the Amazon, fertilizer-driven greenhouse gas emissions, acid rain in industrial zones, and ocean oxygen decline were also considered to contextualise the findings within global environmental patterns.

Burning of fossil fuels increased from 0.6 to 7.5 × 10⁹ g C y⁻¹, reflecting industrial and transport energy demand. Plant assimilation declined ~18% (163 → 134 × 10⁹ g C y⁻¹), and soil carbon inputs fell ~17%, indicating vegetation loss and soil sealing. Industrial nitrogen fixation rose from 0 to 102 × 10⁶ g N y⁻¹, while leaching and runoff grew >3 times, signaling eutrophication risk. Despite a 100% urban supply, ecosystem resilience decreased, and atmospheric CO₂ rose sharply.

Maintaining human needs without degrading the environment requires integrated solutions: electrification, low-carbon materials, precision agriculture, nutrient recovery, and urban greening. Sustainable survival demands partnership, not dominance over the environment.