This chapter delves into the evolving era of global environmental monitoring, with a primary focus on weather, water, and climate systems. This chapter highlights the critical importance of Earth and environmental monitoring in addressing pressing challenges such as climate change, extreme weather events, and resource management. It begins with an exploration of the history and current state of global environmental monitoring systems, including the role of meteorological satellites and ground-based observations in weather forecasting and disaster preparedness. The integration of advanced technologies such as satellite remote sensing, numerical weather prediction models, and climate models is emphasized as key to improving predictive capabilities and supporting the mitigation of climate impacts. This chapter also covers the essential components of weather monitoring, including meteorological instruments and remote sensing systems such as LIDAR and SODAR, which offer invaluable data on atmospheric parameters. Furthermore, this chapter examines the role of space-based satellite observations and radar systems in providing comprehensive monitoring of Earth’s atmosphere, oceans, and land surfaces. This chapter concludes with a forward-looking perspective on the importance of expanding and integrating global observation networks to better address the environmental challenges of the twenty-first century.