Short Answer 
The Earth’s axial tilt, or obliquity, is approximately 23.5 degrees and significantly influences climate and seasonal changes by affecting how sunlight is distributed across the planet. This tilt causes different regions to experience varying amounts of sunlight throughout the year, leading to the seasons, while also resulting in variations in incoming solar radiation based on factors like sunlight angle, daylight duration, and geographical location.
Understanding Axial Tilt
The axial tilt of the Earth, referred to as obliquity, is the angle formed between the Earth’s rotational axis and its orbital plane around the Sun. This tilt is crucial in determining how much sunlight reaches different parts of the Earth. The angle typically is about 23.5 degrees, and it plays a vital role in our climate and seasons.
Impact on Seasons
The axial tilt is responsible for the changing seasons as it causes various regions of the Earth to receive different amounts of sunlight throughout the year. When a hemisphere is tilted towards the Sun, it experiences summer, while the opposite hemisphere, tilted away, experiences winter. This variation leads to a cycle of seasonal changes, affecting temperature and weather patterns.
Variations in Insolation
The combination of the axial tilt and the Earth’s elliptical orbit around the Sun results in varying amounts of insolation (incoming solar radiation) at different locations throughout the year. The factors influencing this variation include:
- Angle of sunlight incidence
- Duration of daylight
- Geographical location
These factors collectively determine how intensely and for how long different areas receive sunlight, leading to significant climatic variations across the globe.