Water & Carbon Cycles

• What is the primary source of rainfall in the Amazon Basin?

  Recycled moisture within the rainforest
• What could happen if a tipping point is reached in the Amazon rainforest?

  More rapid dieback of the rainforest
• What is the timescale of past abrupt climate change evidence?

  10-100 years
• What are Dansgaard-Deschger events associated with?

  Rapid Greenland warming and iceberg discharges
• What factors might trigger Heinrich events?

  Atmospheric or oceanic circulation changes
• What is permafrost?

  Permanently frozen ground in high latitudes
• What do permafrost regions contain that is significant for climate change?

  Old organic carbon deposits
• How much carbon does permafrost hold compared to the atmosphere?

  At least twice the amount of atmospheric CO2
• What happens if a significant fraction of permafrost carbon is released?

  It would increase atmospheric temperatures
• What is the net carbon balance in the Arctic?

  Delicate between uptake and release of carbon
• What role does the active layer of permafrost play?

  It thaws during summer, affecting carbon release
• How does warmer summer temperatures affect permafrost?

  It thickens the active layer, increasing carbon availability
• What can standing water conditions in the Arctic lead to?

  Methane production due to lack of oxygen
• What is the effect of heat diffusion on permafrost?

  It takes time for significant thawing to occur
• What is the definition of abrupt climate change?

  A large-scale change over a few decades
• What happens to ice sheets as they melt?

  Their albedo is reduced, absorbing more heat
• What is the impact of freshwater from melting ice sheets on ocean circulation?

  It reduces salinity and slows deep water formation
• What does ENSO stand for?

  El Niño Southern Oscillation
• How does ENSO affect global climate?

  It impacts temperatures and precipitation worldwide
• What could changes in atmospheric circulation affect?

  The monsoon patterns and rainfall distribution
• What is a potential outcome of changes to the West African monsoon?

  Greening of the Sahara/Sahel region
• What happens as the atmosphere and oceans warm?

  Sea ice melts, lowering ocean albedo
• What is the expected change in Arctic sea ice by 2050?

  Nearly ice-free in September
• What is the definition of a climate tipping point?

  A critical threshold for climate state change
• What is the most likely reversible change expected in the 21st century?

  Decline of Arctic sea-ice
• What did the study on winter carbon emissions from Arctic permafrost reveal?

  Winter emissions may offset summer carbon uptake
• How much carbon was lost from Arctic permafrost regions during winters from 2003 to 2017?

  1.7 billion metric tons
• What is the current status of Arctic permafrost in terms of carbon balance?

  Transitioning from a carbon sink to a source
• What is the implication of increasing winter carbon dioxide losses?

  They could increase by 41% over the next century
• What is the significance of permafrost in the Northern Hemisphere?

  It covers about one quarter of the land area
• What is the relationship between temperature and carbon release from permafrost?

  Warmer temperatures lead to more carbon release
• What is the role of NASA's Arctic-Boreal Vulnerability Experiment?

  To study Arctic carbon emissions and vulnerabilities
• What is the trend in carbon emissions from Arctic permafrost regions?

  Increasing emissions each year
• What is the significance of the findings by Sue Natali and her team?

  Indicates a stronger Arctic carbon source in winter
• What is the impact of fossil fuel reduction on winter carbon emissions?

  It could reduce emissions by 17%
• What is the overall trend of carbon balance in the Arctic region?

  Shifting from a sink to a source of carbon
• What is happening to winter carbon emissions from Arctic regions?

  They are increasing each year.
• How has the role of Arctic regions changed regarding carbon emissions?

  They have shifted from sink to source.
• How much carbon was lost from Arctic permafrost regions each winter from 2003 to 2017?

  1.7 billion metric tons.
• What was the average carbon uptake by vegetation during summer growing seasons from 2003 to 2017?

  1 billion metric tons.