The exponential growth of digital communication, mobile devices, cloud platforms, and Internet of Things (IoT) ecosystems has intensified the energy footprint of information networks, raising urgent concerns regarding environmental sustainability and long-term viability. Green Information Networks (GINs) represent a paradigm shift in network architecture and protocol design, prioritizing energy efficiency, carbon-awareness, and renewable energy integration without compromising performance or security. This paper investigates the evolution of energy-aware architectures and protocols across multiple layers—physical, network, and application—while presenting a comprehensive Trust-by-Design sustainability stack for next-generation infrastructures. Using a design-science methodology, we synthesize findings from prior work in green networking, propose a reference architecture for energy-aware operations, and evaluate real-world testbeds across smart city, healthcare, and telecommunication workloads. Results demonstrate that protocol-level optimizations, AI-driven traffic engineering, and renewable-aware edge–cloud offloading reduce network energy consumption by 27–42% compared to baselines, while maintaining latency within 15% of existing SLAs. We show that carbon intensity per gigabit transferred can be reduced to below 30 gCO₂e in optimized deployments, aligning with 2030 Net Zero trajectories. Our findings reveal that GINs are necessary for the sustainable evolution of information infrastructures, requiring the integration of energy efficiency into every layer of design, governance, and policy.