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Tundra Vegetation to Grow Taller, Greener Through 2100
Context:
- Recent research led by NASA scientists has revealed that the tundra vegetation in the far north is expected to grow taller and greener through the end of the century.
- This transformation is driven by the warming global climate, which is reshaping the vegetation structure of boreal forests and tundra biomes.
Geographical Scope
Boreal Forests:
- Located between 50 and 60 degrees north latitude, encompassing parts of Alaska, Canada, Scandinavia, and Russia.
- These forests are home to evergreens like pine, spruce, and fir.
- They are among the world’s leading purveyors of ecosystem services, including carbon storage and clean water, and they harbour globally significant wildlife populations.
Tundra Biome:
- It is divided into two types: Arctic tundra and Alpine tundra.
- Found farther north, has historically been dominated by shrubs, mosses, and grasses due to permafrost and a short growing season.
- It is characterised by an extremely cold climate, low biotic diversity, simple vegetation structure, limited drainage, reliance on dead organic material for nutrients, and large population oscillations.
Key Highlights:
- The study utilised millions of data points from the Ice, Cloud, and Land Elevation Satellite 2 (ICESat-2) and Landsat missions to track changes in vegetation.
- ICESat-2: Provided nearly 20 million data points using lidar to measure vegetation height.
- Landsat: Supplied tens of thousands of scenes from 1984 to 2020, showing changes in boreal forests.
- Previous studies have noted an increase in high-latitude plant growth moving northward into areas previously dominated by tundra vegetation.
- The new study revealed a significant increase in the presence of trees and shrubs in tundra regions and adjacent transitional forests, where boreal and tundra biomes meet. This shift is expected to persist for at least the next 80 years.
- Scientists observed “positive median height changes” indicating that trees and shrubs are expected to become larger and more numerous in areas where they are currently sparse.
Modelling and Predictions:
- Researchers modelled various future climate scenarios, adjusting for temperature and precipitation changes to forecast future forest structures.
- Advanced computing and big data techniques were employed to analyse extensive datasets and refine climate models.
Implications:
- The increased vegetation could have dual effects on the environment.
- The taller and greener vegetation could absorb more atmospheric carbon dioxide (CO2) through photosynthesis, potentially offsetting some impacts of rising CO2 emissions.
- Carbon absorbed through this process would then be stored in the trees, shrubs, and soil.
- The change in forest structure might accelerate permafrost thawing as darker vegetation absorbs more sunlight. This thawing could release CO2 and methane stored in the soil for thousands of years.
