Final answer:
Climate forecasts are useful long-term because they rely on predictable, long-term atmospheric conditions characterized by average temperature and rainfall over many years, unlike weather forecasts, which focus on short-term changes and become unreliable beyond a 7-10 day period.
Step-by-step explanation:
Understanding Climate Forecasts and Weather Models
When discussing why climate forecasts based on imperfect models may still be useful for decades into the future, it is essential to differentiate between climate and weather. Climate represents the long-term, predictable atmospheric conditions of a specific area and is characterized by consistent seasonal temperature and rainfall patterns over many years. On the other hand, weather refers to short-term atmospheric conditions, typically forecasted for 48-hour cycles. Long-term predictions are considered easier than short-term predictions because climate models focus on average conditions over extended periods, rather than the day-to-day variations tackled by weather models. The inaccuracies in weather forecasts increase significantly as the prediction window extends beyond 7-10 days, whereas climate models, which use different variables, can provide a broad outlook for the future climate without depending on precise daily conditions.
Climate models are regarded differently from weather models due to their scale of analysis. For example, planning an outdoor event in northern Wisconsin during summer rather than winter relies on climate understanding. Historical evidence, such as changes in global temperature, is used to deduce long-term climate trends. However, deviations such as an unseasonably cold day do not reflect the overall climate pattern, which is why climate models do not depend on today's global temperature but on long-term averages and trends.