2100

2100 is a year in the Gregorian calendar, the last year of the 21st century and the 100th year of the millennium. It contains 365 days and is not a leap year in the Gregorian system. The year serves as a long-range horizon used in climate, demographics, and infrastructure planning.

Global population estimates for 2100 vary by scenario. Projections commonly place the world population in the range of about 9 to 12 billion, with central estimates around 11 billion. Growth is expected to slow in many regions, while aging populations, lower fertility in many countries, and continuing urbanization influence social and economic dynamics.

Climate and environment: By 2100, global climate change is projected to persist under most scenarios. Global mean temperature could rise by roughly 2–4°C relative to pre-industrial levels, with higher increases under strong emission pathways. Sea-level rise is projected to be on the order of 0.3 to 1.0 meters by 2100, depending on ice-sheet behavior and regional factors. Impacts include shifts in weather patterns, greater frequency of extreme events, and regional variations in water resources and agriculture.

Technology and energy: The energy system is expected to shift toward low-carbon and renewable sources, with continued electrification of transport and heating. Advances in digital technologies, artificial intelligence, biotechnology, and automation are likely to reshape economies and labor markets, accompanied by policy considerations around governance, privacy, and resilience.

Significance: 2100 serves as a long-term horizon for policy, climate adaptation, and research, guiding planning for infrastructure, risk management, and sustainable development.