Last year, Longyearbyen recorded an average July temperature over 10°C, challenging the traditional polar climate definition that typically inhibits tree growth. This trend continued with record-high temperatures in Svalbard and East Finnmark in 2024, where COAT weather stations on the Varanger Peninsula recorded temperatures 3-4 degrees above the tree growth threshold.
These temperature records are not random. Statistical analysis shows that such high temperatures in Vardø and Longyearbyen are extremely rare events, suggesting that recent temperature spikes are linked to ongoing Arctic climate changes rather than yearly weather variability.
Recent studies have refined the criteria for tree growth in Arctic regions, indicating that a combination of the length of the growing season and average temperature is more accurate than the classical 10-degree rule. For instance, the growing season should last at least 94 days with temperatures above 0.9°C, and the average temperature should be at least 6.4°C. These conditions were met in both 2023 and 2024 at various COAT stations, suggesting potential for tree growth.
However, transitioning from tundra to forest can take centuries, even under suitable climate conditions, due to ecological and biological barriers. Rapid Arctic climate changes necessitate comprehensive ecosystem monitoring, as demonstrated by COAT, to manage and adapt to these transformations effectively.
