1 year ago

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Drought and Storm

 

 

 

 

 

Every year and everywhere the effects of climate change become more apparent. Violent downpours throw the sky into turmoil and droughts harden it in a blue that comes to seem cruel.  Over the last year enough coal, oil and gas was burned globally to add 1% to the total carbon dioxide in the atmosphere and oceans. (more)

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Changes in rainfall 1981-2010 relative to 1951-1980,    Paths of major storms

 
Adapted from Vogt, J. et al (2018) and NOAA Hurricane Center maps

Drought

Severe Drought

Extreme Drought

Increased Rainfall

Severely Increased Rainfall

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Measures over one year compared with recent benchmarks

 
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7.8 billion

Global Population

rising by ~ 1%/year

Rate is slowing

415 parts per million

Carbon Dioxide Concentration

rises and falls in yearly cycle

Average is rising by ~ 1%/year

14.9°C

Global Average Temperature

rising irregularly

21 centimeters

Sea Level above level in 1900

rising by ~ 3.2 cm/year

Rate is accelerating

6.1 billion

Population in 2000

320 ppm

20th century median

13.9°C

20th-century average

Sea level in 1900 is datum

Year to Year

Over the course of a year the Earth breathes, absorbing carbon dioxide into new plant growth in spring and summer, then releasing it in fall and winter when plants die and decompose.  This annual oscillation cycles carbon through the living world without changing the overall quantity in the ecosystem.  Because the northern hemisphere has more land than the southern, the quantity of carbon dioxide in the air globally rises and falls with northern seasons. 

 

In spring when ice retreats, old plant material is exposed and warmed, accelerating decomposition, the total quantity of carbon dioxide the air crests, then starts to decline as new plants and leaves sprout into the sunlight, growing fast. In summer when the sun is high and warmth extends far north, massive forests of Russia and Canada reach their peak growth rate, drawing in carbon dioxide across a vast landscape.  In autumn, growth slows, leaves fall and rot, releasing their carbon dioxide into the air until the ice returns.

Year to year, as emissions add carbon to this cycle, the seasons still change; winter is still cold, summer warm, yet every year the weather becomes less stable, threatening agricultural stability worldwide. 

Temperatures in the far north are most radically affected.  Greenland and the Arctic are seeing

temperatures 26°C above historical averages, sometimes well above the freezing point.  The warming arctic also weakens the jet stream to the extent that winter polar air can penetrate to middle latitudes, bringing brutal cold, sometimes for weeks.  In summer the same jet stream can stall in one position, allowing heat to build without respite to deadly temperatures, particularly in cities. Higher summer temperatures draw more moisture from the ground, exacerbating droughts in some areas and building storm clouds in others, which can release deluges of water in hours.  The heat also warms the ocean, fueling summer cyclones to the highest wind speeds ever recorded. And carbon dioxide absorbed by the oceans acidifies the water, threatening corals, shellfish and some plankton at the foundation of the marine food chain.

 

The annual cycle also offers opportunities for renewable energy in concert with the seasons.  Solar energy peaks with the summer solstice, just as the weather gets hot and air conditioners turn on.  In winter the wind kicks up across the northern latitudes stirred by temperature differences.  Agricultural techniques such as permaculture and agroforestry, which shift from annual planting to perennial species, shade and protect the soil, allowing it to hold moisture and absorb rainwater, mitigating both drought and flooding.

 

References

Text: Samenow, J. (2019). Temperatures leap 40 degrees above normal as the Arctic Ocean and Greenland ice sheet see record June melting. Washington Post.(June 14, 2019) Washington DC.

Image: Composite of images from Adobe Stock 

Map:  Vogt, J., et al. (2018). Drought Risk Assessment and Management: a conceptual Framework  Luxembourg, Publications Office of the European Union. https://www.researchgate.net/publication/329451050

National Ocean Service NOAA. (2018). "NOAA Historical Hurricane Tracks."   Retrieved 20 September 2018, 2018, from https://oceanservice.noaa.gov/news/historical-hurricanes/.

CO2: Scripps Institution of Oceanography. (2018). "The Keeling Curve: Carbon dioxide concentration at Mauna Loa Observatory."   Retrieved 20 September 2018, from https://scripps.ucsd.edu/programs/keelingcurve/.

Temperature: NASA Goddard Institute for Space Studies. (2018). "Global Temperature 2017: Monthly Temperature Anomalies."   Retrieved 20 September, 2018, from https://climate.nasa.gov/vital-signs/global-temperature/.

Sea Level: NASA Goddard Space Flight Center. (2018). "Sea Level:  Satellite Data: 1993-Present." Global Climate Change: Vital Signs of the Planet,  Retrieved 20 September, 2018, from https://climate.nasa.gov/vital-signs/sea-level/.

Population: Worldometers. (2018). "World Population by Year." Retrieved 20 September, 2018 from http://www.worldometers.info/world-population/world-population-by-year/.

Contact:  readg@fiu.edu
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