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Earth's Systems / Biological processes / Terrestrial ecosystem functioning / Organism-environment interactions / Vegetation, snow, albedo and carbon feedbacks across scales

Vegetation, snow, albedo and carbon feedbacks across scales

Plants and soil microbes link small-scale processes to regional and global climate: shrub expansion, snow trapping, darker surfaces, soil warming and carbon release can amplify warming, while vegetation-rain coupling can amplify or damp drought.

Boundary: where this process starts

Starts with: Warming lengthens the growing season and shrubs expand into tundra

Boundary: where it ends

Ends after: Vegetation-rain coupling amplifies drought or wet spells (Sahel and boreal examples); Darker, taller canopy absorbs more sunlight and lowers albedo

PARTICIPANTSRESOURCESSoil microbesAtmosphereShrubsPlantsVegetationHeatNitrogenSoil organicmatterSnowAmmoniumImpact +3 of 5. Click for details and evidence.Impact +3 of 5. Click for details and evidence.Impact +3 of 5. Click for details and evidence.Impact +3 of 5. Click for details and evidence.Impact +3 of 5. Click for details and evidence.↻ reinforces · moderate · 0.3 more shrubs, mImpact -3 of 5. Click for details and evidence.Impact +3 of 5. Click for details and evidence.↻ reinforces · weak · 0.15 darker surface abImpact +3 of 5. Click for details and evidence.Impact +2 of 5. Click for details and evidence.↻ reinforces · weak · 0.1 released CO2 adds Impact 01 of 5. Click for details and evidence.Impact 02 of 5. Click for details and evidence.Impact 02 of 5. Click for details and evidence.Warming lengthens the growing season and shrubs expand into tundra: uses HeatWarming lengthens the growing season and shrubs expand into tundra: uses NitrogenShrubs trap more snow, insulating soil so winter soil stays warmer: uses HeatShrubs trap more snow, insulating soil so winter soil stays warmer: uses SnowWarm winter soil speeds microbial decomposition and nitrogen mineralisation: makes NitrogenmakesWarm winter soil speeds microbial decomposition and nitrogen mineralisation: uses up Soil organic matteruses upWarm winter soil speeds microbial decomposition and nitrogen mineralisation: makes AmmoniummakesGreater nutrient supply lets shrubs grow taller and denser: uses NitrogenDarker, taller canopy absorbs more sunlight and lowers albedo: uses HeatLocal warming and fertile soil speed decomposition and carbon release: uses up Soil organic matteruses upwarmth extends theseasonHeat: warmth extends the seasonreleased faster fromthawing soilNitrogen: released faster from thawing soilinsulated and retainedin soilHeat: insulated and retained in soiltrapped by dense shrubstemsSnow: trapped by dense shrub stemsmineralised and releasedNitrogen: mineralised and releasedbroken down by microbesSoil organic matter: broken down by microbesproduced by decomposingmicrobesAmmonium: produced by decomposing microbesfuels taller, densergrowthNitrogen: fuels taller, denser growthabsorbed as the surfacewarmsHeat: absorbed as the surface warmsdecomposed by warmmicrobesSoil organic matter: decomposed by warm microbesStart: Vegetation,snow, albedo and carbonfeedbacks across scalesSTARTStart: Vegetation, snow, albedo and carbon feedbacks across scalesEnd: Vegetation, snow,albedo and carbonfeedbacks across scalesENDEnd: Vegetation, snow, albedo and carbon feedbacks across scalesWarming lengthens thegrowing season andshrubs expand in…📄1Warming lengthens the growing season and shrubs expand into tundraShrubs trap more snow,insulating soil sowinter soil sta…📄1 ↗1Shrubs trap more snow, insulating soil so winter soil stays warmerWarm winter soil speedsmicrobial decompositionand nitrog…📄1Warm winter soil speeds microbial decomposition and nitrogen mineralisationGreater nutrient supplylets shrubs grow tallerand denser👍1📄1Greater nutrient supply lets shrubs grow taller and denserDarker, taller canopyabsorbs more sunlightand lowers albedo📄1 ↗1Darker, taller canopy absorbs more sunlight and lowers albedoLocal warming andfertile soil speeddecomposition a…📄1 ↗2Local warming and fertile soil speed decomposition and carbon releaseVegetation-raincoupling amplifiesdrought or wet spel…📄1 ↗1Vegetation-rain coupling amplifies drought or wet spells (Sahel and boreal examples)
Line thickness = size of impact (1 to 5)% on a line = chance a fork takes that branch📄 = pieces of evidence on a stepNegative effectLoops backHypothesisResource used up (arrow into the step)Resource used, not used upResource made or released (arrow out of the step)
What am I looking at? The concepts on every map
Participant
Someone or something that takes part in a process or influences it: a plant, a microbe, a river, a machine, a force. Participants are the rows of a map.
Resource
Something a step uses or uses up: water, oxygen, sunlight, a tool. Each step has an arrow down to the resources it uses.
Step
One thing that happens in a process. Every step has at least one participant and carries evidence.
Decision fork
A step where the process can go several ways. Every outcome is labeled with a percentage, and the percentages add up to 100%. It is not limited to yes or no.
Loop
A line that carries the process back to an earlier step. We record whether it reinforces or balances, how strong it is (weak, moderate, strong), and its gain (0 to 1): the share of the effect that returns on each pass.
Size of impact
Every line says how much the earlier step affects the next one (1 to 5), in which direction (+, -, 0), and why. Thicker lines mean bigger impact.
Evidence
The support for a claim: a source and what it shows. Every step, line, change and vote needs it. Click any step or line to read its evidence.
Boundary
Where a process starts and where it ends. Every process, and every subprocess, has a start and an end.
Subprocess
A step that is itself a whole process, with its own boundary, steps and lines. Click a step marked ↘ to open it. Subprocesses nest as deep as the evidence goes.
Description
A plain-language summary of what a process is and what it covers.
Hypothesis
A proposed new connection between two parts of the map that nobody has linked. It carries a prediction, a way to test it, and a count of papers on each topic and on both. It is an unverified idea until someone tests it.

Every step, with its evidence

The same information as the map, as a list you can search and share. Click a participant or resource to see everywhere it appears.

Warming lengthens the growing season and shrubs expand into tundra
ShrubsClimateHeatNitrogen
Evidence (1) · added by Loopa
  • Sturm 2005, Winter biological processes could help convert arctic tundra to shrubland, BioScience, doi:10.1641/0006-3568(2005)055[0017:wbpchc]2.0.co;2: Shrub expansion could convert tundra to shrubland through biological winter processes. (confidence 0.8)
Shrubs trap more snow, insulating soil so winter soil stays warmer
ShrubsSnowpackSnowHeat
Evidence (1) · added by Loopa
  • Sturm 2005, Winter biological processes could help convert arctic tundra to shrubland, BioScience, doi:10.1641/0006-3568(2005)055[0017:wbpchc]2.0.co;2: Snow-shrub interactions warm winter soil. (confidence 0.8)
Warm winter soil speeds microbial decomposition and nitrogen mineralisation
Soil microbesNitrogenAmmoniumSoil organic matter
Evidence (1) · added by Loopa
  • Sturm 2005, Winter biological processes could help convert arctic tundra to shrubland, BioScience, doi:10.1641/0006-3568(2005)055[0017:wbpchc]2.0.co;2: Winter microbial activity releases nutrients that favour shrubs. (confidence 0.8)
Greater nutrient supply lets shrubs grow taller and denser
ShrubsNitrogenLight
Evidence (1) · added by Loopa
  • Mack 2004, Ecosystem carbon storage in arctic tundra reduced by long-term nutrient fertilization, Nature, doi:10.1038/nature02887: Nutrient addition changed arctic plant composition toward shrubs. (confidence 0.8)
Darker, taller canopy absorbs more sunlight and lowers albedo
VegetationSunSunlightHeat
Evidence (1) · added by Loopa
  • Eugster 2000, Land-atmosphere energy exchange in Arctic tundra and boreal forest, Global Change Biology, doi:10.1046/j.1365-2486.2000.06015.x: Tundra and boreal surface energy exchange differs strongly from open ground and snow. (confidence 0.8)
Local warming and fertile soil speed decomposition and carbon release
Soil microbesCarbon dioxideSoil organic matter
Evidence (1) · added by Loopa
  • Mack 2004, Ecosystem carbon storage in arctic tundra reduced by long-term nutrient fertilization, Nature, doi:10.1038/nature02887: Long-term fertilisation lowered ecosystem carbon storage in tundra by soil carbon loss exceeding plant gain. (confidence 0.8)
Vegetation-rain coupling amplifies drought or wet spells (Sahel and boreal examples)
VegetationAtmosphereWater vapourWater
Evidence (1) · added by Loopa
  • Zeng 1999, Enhancement of interdecadal climate variability in the Sahel by vegetation interaction, Science, doi:10.1126/science.286.5444.1537: Vegetation interaction enhanced interdecadal rainfall variability in the Sahel model. (confidence 0.8)