While winter Seasonal Affective Disorder (SAD) is well-known, a reverse pattern exists where summer's excessive light and heat can cause agitation, anxiety, and low mood, challenging the universal view of summer as a positive season.
Our cognitive style shifts with the weather. Sunshine encourages broad, creative thinking and social engagement, whereas cloudy or rainy conditions narrow our focus, making us more careful, analytical, and detail-oriented. This directly impacts decision-making and evaluation.
Population-level data reveals a link between being born in winter and a slightly increased risk for conditions like schizophrenia and major depression. This is not astrology but reflects early developmental factors like maternal vitamin D levels, daylight exposure, and viral infections.
The defining environmental pressure that shaped humanity was a tens-of-millions-of-years decline in CO2, which triggered the volatile Pleistocene ice ages. This cold climate drove the development of fire, large brains, and complex sociality. We are fundamentally creatures of a low-CO2 world.
The vast majority of a plant's mass is derived from carbon dioxide pulled from the atmosphere during photosynthesis, not nutrients from the ground. This means life is fundamentally built from the air. Consequently, when you lose weight, you are literally breathing it out as CO2.
The planet's climate is extraordinarily sensitive. Over the last 50 million years, a fluctuation between just 0.1% and 0.018% atmospheric CO2 determined whether the Arctic had palm trees or North America was covered in ice, highlighting the gravity of current emissions.