Systems Gallery · Earth & Env Science

← Back to Unit 1 · Block 2b · Unit 1 · Block 7

How to use a card

Pick one card. Six are in Chennai, six are global; the first arrow is already written so you do not start blank.
Copy its note frame onto paper: four lines, in that order. Line 1 is written for you. Line 2 needs a verb: the card's Return arrow question tells you what to look for. Line 3 is the sign test from Step 6: circle bigger or smaller, say why, circle + or −. Line 4 names the sphere from Grow to; you add the verb.
Draw what you wrote, the same way you drew Step 4 to Step 7 in Build Your First Systems Diagram: two circles and the first arrow, the return arrow, the sign, then the next sphere. The drawing below shows where each line goes.

What a finished card looks like on paper. This is card 7, Arctic ice and sunlight. Number 1 is the first arrow, 2 is the return arrow, 3 is the sign and its sentence, 4 is the third sphere. Your card will have different words in the same four places.

The monsoon and the Bay

Chennai · Hydrosphere and Atmosphere

First arrow

Hydrosphere (the Bay of Bengal) evaporates into atmosphere.

Return arrow

What does the air send back to the Bay, and to Chennai's streets, when the northeast monsoon arrives in November?

Sign

A warmer bay evaporates more; ask what more water vapor in the air does to the heat the bay feels next.

Grow to

Geosphere joins first: rain soaks into the ground, or runs off the built surface into the Adyar.

Sources

NASA Earth Observatory, Historic Rainfall Floods Southeast India (2015)Origin: NASA Earth Observatory, a US government science agency, published this in December 2015 to explain satellite rainfall data from the Chennai floods to the public.
UCAR Center for Science Education, What Are Monsoons and Why Do They Happen?Origin: The UCAR Center for Science Education, the teaching arm of a US university research consortium, publishes this page to teach students what monsoons are and why they happen.

Note frame

First arrow, written for you: Hydrosphere evaporates into atmosphere.
Return arrow, your verb: Atmosphere ______ hydrosphere.
Sign test, your words: I pushed ______ up, and it came back bigger / smaller, because ______. Sign: + / −
Next sphere, your verb: Geosphere joins by ______.

Reservoirs at zero, June 2019

Chennai · Hydrosphere and Geosphere

First arrow

Hydrosphere (Puzhal reservoir) seeps into geosphere (as groundwater).

Return arrow

When the reservoir is empty and every borewell is pumping, what does the ground send back to the city's water supply, and what happens when it cannot?

Sign

Pump more groundwater in a dry year and ask whether the emptier ground refills faster, or dries the land further.

Grow to

Atmosphere joins first: a failed northeast monsoon rains less onto the reservoir.

Sources

NASA Earth Observatory, Water Shortages in India (June 2019)Origin: NASA Earth Observatory, a US government science agency, published this in June 2019 to show Landsat satellite images of Puzhal Lake near Chennai before and after the reservoirs ran dry.

Note frame

First arrow, written for you: Hydrosphere seeps into geosphere.
Return arrow, your verb: Geosphere ______ hydrosphere.
Sign test, your words: I pushed ______ up, and it came back bigger / smaller, because ______. Sign: + / −
Next sphere, your verb: Atmosphere joins by ______.

Pallikaranai marsh as a sponge

Chennai · Biosphere and Hydrosphere

First arrow

Biosphere (marsh plants and their soil) soaks up hydrosphere (floodwater).

Return arrow

What does the stored water send back to the marsh's plants and birds in the dry months?

Sign

Fill in more of the marsh with buildings and ask whether the next flood is absorbed more, or less.

Grow to

Geosphere joins first: the marsh recharges groundwater in the rock below it.

Sources

Ramsar Sites Information Service, Pallikaranai Marsh Reserve Forest (site 2481)Origin: The Ramsar Convention Secretariat, an intergovernmental treaty body, publishes this information sheet because India designated Pallikaranai a Wetland of International Importance in April 2022.
Tamil Nadu State Wetlands Authority, Pallikaranai Marsh Reserve ForestOrigin: The Tamil Nadu State Wetlands Authority, a state government body, publishes this page to record the marsh's features and its protected status.

Note frame

First arrow, written for you: Biosphere soaks up hydrosphere.
Return arrow, your verb: Hydrosphere ______ biosphere.
Sign test, your words: I pushed ______ up, and it came back bigger / smaller, because ______. Sign: + / −
Next sphere, your verb: Geosphere joins by ______.

Coral bleaching, Gulf of Mannar

Chennai · Hydrosphere and Biosphere

First arrow

Hydrosphere (warm sea water) warms biosphere (the coral).

Return arrow

What does a living reef send back to the water around it, and what stops when the coral bleaches?

Sign

Push the sea temperature up for a few weeks and ask whether the reef pushes back against that heat, or simply loses the algae that feed it.

Grow to

Atmosphere joins first: a warmer atmosphere heats the sea surface.

Sources

NOAA Coral Reef Watch, Bleaching ThresholdOrigin: NOAA Coral Reef Watch, a program of a US government ocean agency, publishes this tutorial to explain how its satellite temperature products predict bleaching.

Note frame

First arrow, written for you: Hydrosphere warms biosphere.
Return arrow, your verb: Biosphere ______ hydrosphere.
Sign test, your words: I pushed ______ up, and it came back bigger / smaller, because ______. Sign: + / −
Next sphere, your verb: Atmosphere joins by ______.

Pichavaram mangroves and the shore

Chennai · Biosphere and Geosphere

First arrow

Biosphere (mangrove roots) traps geosphere (sediment).

Return arrow

What does the built-up mud send back to the mangroves that lets them spread?

Sign

More roots trap more mud; ask whether more mud grows more mangroves.

Grow to

Hydrosphere joins first: the roots slow the tidal water that carries the sediment in.

Sources

NOAA National Ocean Service, What is a mangrove forest?Origin: NOAA's National Ocean Service, a US government agency, publishes this Ocean Facts page to answer a public question about what a mangrove forest is and does.

Note frame

First arrow, written for you: Biosphere traps geosphere.
Return arrow, your verb: Geosphere ______ biosphere.
Sign test, your words: I pushed ______ up, and it came back bigger / smaller, because ______. Sign: + / −
Next sphere, your verb: Hydrosphere joins by ______.

Chennai heat island

Chennai · Geosphere and Atmosphere

First arrow

Geosphere (built surfaces: roads, roofs, concrete) absorbs and re-radiates heat into atmosphere.

Return arrow

What does hotter air over the city send back down to the concrete at night?

Sign

Add more concrete and ask whether the air over the city gets hotter, and whether hotter air cools the concrete or keeps it warm.

Grow to

Biosphere joins first: trees shade the surfaces and breathe out water vapor that cools the air.

Sources

US EPA, What Are Heat Islands?Origin: The US Environmental Protection Agency, a government regulator, publishes this page to explain heat islands to communities planning how to cool their cities.

Note frame

First arrow, written for you: Geosphere absorbs and re-radiates heat into atmosphere.
Return arrow, your verb: Atmosphere ______ geosphere.
Sign test, your words: I pushed ______ up, and it came back bigger / smaller, because ______. Sign: + / −
Next sphere, your verb: Biosphere joins by ______.

Arctic ice and sunlight

Global · Hydrosphere and Atmosphere

First arrow

Hydrosphere (sea ice) reflects sunlight back into atmosphere.

Return arrow

What does a warmer atmosphere send back to the ice?

Sign

Melt a little ice and ask what the dark open water does with the sunlight the ice used to reflect.

Grow to

Biosphere joins first: less ice changes where plankton and seals can live.

Sources

NSIDC, Science of Sea IceOrigin: The National Snow and Ice Data Center, a US university research center funded by NASA and NOAA, publishes this page to explain the science of sea ice, including albedo, to the public.

Note frame

First arrow, written for you: Hydrosphere reflects sunlight back into atmosphere.
Return arrow, your verb: Atmosphere ______ hydrosphere.
Sign test, your words: I pushed ______ up, and it came back bigger / smaller, because ______. Sign: + / −
Next sphere, your verb: Biosphere joins by ______.

The Amazon's flying rivers

Global · Biosphere and Atmosphere

First arrow

Biosphere (the forest) breathes out water vapor into atmosphere.

Return arrow

What does the atmosphere send back down onto the forest?

Sign

Cut some forest and ask whether the rain that fed the rest of it still arrives.

Grow to

Hydrosphere joins first: the rain feeds the rivers the forest drinks from.

Sources

NASA Earth Observatory, The Amazon Makes its Own Wet Season (2017)Origin: NASA Earth Observatory, a US government science agency, published this in October 2017 to report a NASA-funded satellite study of how Amazon trees start their own rainy season.

Note frame

First arrow, written for you: Biosphere breathes out water vapor into atmosphere.
Return arrow, your verb: Atmosphere ______ biosphere.
Sign test, your words: I pushed ______ up, and it came back bigger / smaller, because ______. Sign: + / −
Next sphere, your verb: Hydrosphere joins by ______.

Permafrost thaw

Global · Geosphere and Atmosphere

First arrow

Geosphere (thawing frozen soil) releases carbon dioxide and methane into atmosphere.

Return arrow

What does an atmosphere holding more greenhouse gas send back to the frozen ground?

Sign

Thaw a little more ground and ask whether the gas it releases makes the next thaw slower, or faster.

Grow to

Biosphere joins first: microbes in the thawed soil are what turn the old carbon into gas.

Sources

NOAA Arctic Report Card 2019, Permafrost and the Global Carbon CycleOrigin: NOAA's Arctic Report Card, a peer-reviewed annual from a US government agency, published this 2019 essay by permafrost scientist Ted Schuur to summarise what is known about permafrost carbon.

Note frame

First arrow, written for you: Geosphere releases carbon dioxide and methane into atmosphere.
Return arrow, your verb: Atmosphere ______ geosphere.
Sign test, your words: I pushed ______ up, and it came back bigger / smaller, because ______. Sign: + / −
Next sphere, your verb: Biosphere joins by ______.

Ocean acidification

Global · Atmosphere and Hydrosphere

First arrow

Atmosphere (carbon dioxide) dissolves into hydrosphere.

Return arrow

What does the sea send back to the air, and does holding more carbon change how much more it can keep taking?

Sign

Add more carbon dioxide to the air and ask whether a more acidic ocean absorbs the next tonne more easily, or less.

Grow to

Biosphere joins first: shell-building animals struggle to build in the more acidic water.

Sources

NOAA PMEL, Ocean Acidification: The Other Carbon Dioxide ProblemOrigin: NOAA's Pacific Marine Environmental Laboratory, a US government research lab, publishes this page to explain the ocean acidification research it runs.

Note frame

First arrow, written for you: Atmosphere dissolves into hydrosphere.
Return arrow, your verb: Hydrosphere ______ atmosphere.
Sign test, your words: I pushed ______ up, and it came back bigger / smaller, because ______. Sign: + / −
Next sphere, your verb: Biosphere joins by ______.

Volcanoes and the slow carbon cycle

Global · Geosphere and Atmosphere

First arrow

Geosphere (volcanoes) outgasses carbon dioxide into atmosphere.

Return arrow

What does a warmer, wetter atmosphere send back onto the rock over thousands of years?

Sign

Warm the air and ask whether more rain and weathering pulls carbon dioxide out of the air faster, and what that does to the warmth.

Grow to

Hydrosphere joins first: rain carries the weathered carbon to the sea, where it is buried as limestone.

Sources

USGS Volcano Hazards Program, Volcanoes Can Affect ClimateOrigin: The US Geological Survey Volcano Hazards Program, a government science agency, publishes this page to explain how volcanic gases cool or warm the climate.

Note frame

First arrow, written for you: Geosphere outgasses carbon dioxide into atmosphere.
Return arrow, your verb: Atmosphere ______ geosphere.
Sign test, your words: I pushed ______ up, and it came back bigger / smaller, because ______. Sign: + / −
Next sphere, your verb: Hydrosphere joins by ______.

Water vapor, the loop that amplifies

Global · Hydrosphere and Atmosphere

First arrow

Hydrosphere evaporates into atmosphere.

Return arrow

What does the air send back to the sea, and what does the extra vapor in the air do to the heat the sea receives?

Sign

You signed this loop in Step 6 of the tutorial; the source tells you how much it multiplies the warming.

Grow to

Geosphere joins first: rain soaks into groundwater, exactly as in the tutorial.

Sources

NASA, Steamy Relationships: How Atmospheric Water Vapor Amplifies Earth's Greenhouse EffectOrigin: NASA, the US space agency, published this explainer in February 2022 to describe how water vapor amplifies the greenhouse effect.

Note frame

First arrow, written for you: Hydrosphere evaporates into atmosphere.
Return arrow, your verb: Atmosphere ______ hydrosphere.
Sign test, your words: I pushed ______ up, and it came back bigger / smaller, because ______. Sign: + / −
Next sphere, your verb: Geosphere joins by ______.

Where this goes

Block 7 is where the systems-thinking strand gets graded: the last field of every habitability criterion asks where it can fail, and that is a feedback loop in disguise. A gallery diagram with a signed loop and a cited source is exactly the evidence it wants. Keep the drawing, keep the source's Origin line, and bring both.

Done here? Back to the lesson: ← Unit 1 · Block 2b ← Unit 1 · Block 7