Climate Connections
Making Sense of Seasonal Observations
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What Scientists Wonder
Scientists gather long-term data on the timing of natural events such as the return of a migrating animal. Then they compare it with climate data for the same period. They may discover patterns of change (e.g., between temperatures and the average date of return of a species). Next, they ask, How might this directly or indirectly affect a plant or animal’s ability to meet its basic needs and reproduce?
How is Seasonal Change Linked to Climate?

Since early history, humans have been aware of seasonal changes in plant and animal life cycles. Phenology is the study of the timing of these changes. Animals hibernate or migrate, leaves grow, flowers bloom, insects hatch, and so on. After thousands or millions of years of evolution, these events are naturally matched with a species’ biological needs to find food, reproduce, and otherwise survive. Daylength — which changes predictably throughout the year — and a region’s climate (especially temperature and rainfall) determine when these events typically unfold.

Plants and animals can handle natural variations in weather from season to season and year to year. For instance, some years are colder or wetter on average. But as long-term weather patterns (climate) have changed more rapidly – and dramatically – than ever before, the average timing of many life cycle events has shifted. This has put some species out of synch with food chains and other parts of the ecosystems they depend on.

These changes happen slowly enough that we wouldn’t notice them day to day. But tracking them over many years can give us clues about climate change and its impact on the health of living things and entire ecosystems. Through Journey North, students can join scientists and other citizens in making these important observations.

Next: How Can a Changing Climate Affect Plants and Animals? >>


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