Where the Rain Falls

The Baseline · Visualization 1

The Rhythm We Built Civilization On

Before we can understand what is changing, we need to see what was stable. For centuries, global precipitation followed a reliable seasonal cycle — ecosystems, agriculture, and entire economies were built around it. This baseline, drawn from CESM2 climate model output for 1980–2010, shows the pattern humanity depends on.

Drag the dashed line to set a threshold Hover a bar to see exact value

Global Precipitation Seasonal Cycle · 1980–2010

CESM2 · r1i1p1f1 · Historical run · Global spatial mean (mm/day)

↕ DRAG THRESHOLD

June – July Peak precipitation months globally — driven by the Northern Hemisphere monsoon season and the Intertropical Convergence Zone migrating north.

~2.42 mm/day The global mean — the dashed threshold line. Drag it up or down to see which months fall above or below any precipitation level you choose.

Why this matters Climate projections show this curve is already shifting — wet months are getting wetter and dry months drier. What looks like a small change in mm/day translates to catastrophic floods and multi-year droughts.

Global Shift · Visualization 2

Where the Rain Is Moving

Now we project forward. This map shows how decadal-mean precipitation departs from the 1980–2010 baseline, as a percentage — brown for drier, teal for wetter. Drag the timeline from 1980 to 2100 to watch the subtropical dry zones expand while high latitudes and tropics moisten — then switch the emissions pathway to compare a low-, middle-, and high-carbon future.

Drag the timeline slider to travel through time Switch the emissions pathway to compare futures Press Play to animate 1980 → 2100

Decadal Precipitation Change vs. 1980–2010 Baseline

CESM2 · historical + SSP5-8.5 (high emissions) · % change in mean precipitation

Emissions pathway

Δ% precip

Global-mean precipitation change under all three pathways — the highlighted line tracks the selected scenario.

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Loading scenarios…

Regional Extremes · Visualization 3

A Tale Of Extremes

Global averages hide violent local contrasts. The Amazon rainforest receives more than 2,000 mm/year. The Sahara averages less than 25 mm. These extremes are not static — climate projections show they will intensify. Explore the extremes — then search your own city, country, or region to see what the data says about its future.

Search your city, country, or region Click a card or pin to zoom in Drag globe to rotate freely Use ← Back to globe to return

🌿 The Amazon Rainforest

A critical global carbon sink receiving ~6 mm/day. Under SSP5-8.5, its dry season is projected to extend by 3–4 weeks by 2080, threatening 1 billion+ who depend on Amazon-regulated rainfall for agriculture.

🏜 The Sahara Desert

Averaging under 0.07 mm/day — one of Earth's driest places. Climate models project the arid belt to expand equatorward and poleward, pushing desertification into currently productive land across North Africa and Southern Europe.

🌧 Mawsynram, India

The wettest place on Earth at ~11,871 mm/year. The South Asian monsoon is projected to intensify 5–20% under high emissions — more total rain, but delivered in shorter, more violent bursts that overwhelm infrastructure.

📍 Find Your Region

Beyond the extremes, search any city, country, or region to see its own projected trajectory. Every place maps to one of the 46 IPCC AR6 reference regions — the standardized sub-continental zones climate scientists use to summarize regional change.

Amazon Rainforest · Projected Change

Historical avg (1980–2010) ~6.0 mm/day

Projected avg by 2080 (SSP5-8.5) ~5.4 mm/day

Dry season extension +3–4 weeks

Risk to agriculture Critical

Sahara Desert · Projected Change

Historical avg (1980–2010) ~0.07 mm/day

Projected avg by 2080 (SSP5-8.5) ~0.05 mm/day

Arid belt expansion +200–400 km

Affected population ~250 million

Mawsynram, India · Projected Change

Historical avg (1980–2010) ~32.5 mm/day

Projected avg by 2080 (SSP5-8.5) ~36–39 mm/day

Monsoon intensity increase +10–20%

Flood risk change Severe increase

Region · Projected Change

Change by 2100 (SSP5-8.5) —

Direction —

The Consequences · Visualization 4

When the Rain Falters, So Does Vegetation

Shifting precipitation doesn’t just change the weather, it also rewires ecosystems and agriculture. Using the same CMIP6 CESM2 model, we project the Leaf Area Index (LAI), a measure of vegetation density and health in various regions. The map below shows how vegetation is expected to change by (2070–2100) under the high‑emissions SSP5‑8.5 scenario.

Projected vegetation change by latitude band

LAI % change (2070–2100 mean vs. 1980–2010 baseline)

Hover any bar to see the exact change and the food security impact

Tropics: –11% LAI

Reduced canopy cover, drier soils. We can observe a 12-18% drop for rain-fed maize and rice yields in South Asia and Sub-Saharan Africa. Over 1.2 billion people are projected to face food insecurity by 2080.

Southern Mid‑Latitudes: –8% LAI

The vast agricultural center becomes drier and drier with time. Livestock carrying capacity declines, threatening exports and the ability to supply protein.

Northern Mid‑Latitudes: +5% LAI

The initialiiy green Boreal forests diminish due to increased wildfire risk and permafrost (any ground that remains frozen for at least 2 years). The timber industry suffers greatly.

Under high emissions, tropical vegetation declines by more than 10% which is the equivalent of losing an entire month of growing. For 1.2 billion people, this means a 15% drop in available food, leading to chronic food stress.

🌍🌾

The Core Takeaway: Water Moves, Farms Cannot

If there is one thing to learn from this data, it is that shifting rain is fundamentally a global food security crisis. Our agricultural systems are locked into place, but the water they rely on is migrating away from the subtropics.

As precipitation drops, the vegetation essential for our survival dies, cascading directly into crop failures and threatening global stability.

📉🔗

Tracing the Chain of Events

Our visualizations were structured to prove this exact cascading failure. We began by establishing the fragile rhythm of our historical climate (Vis 1).

We then proved how drastically global and regional water patterns will diverge from that baseline (Vis 2 & 3). Finally, we mapped the ultimate consequence: missing rain directly equals dying canopies and food stress (Vis 4).

🎯💡

Why This Narrative Works

Climate data is famously abstract and difficult to grasp. This project succeeds because it makes a global crisis intimately personal.

By allowing users to set their own thresholds, compare future scenarios, and specifically search their own hometowns on a 3D globe, we transform distant, complex climate models into tangible, localized, and undeniable human consequences.

We opened by asking where the water would fall — and where it would vanish.

You've watched it move. Here's what moves with us.

A warming planet is, before anything else, a story about water — rain is moving, not simply rising or vanishing everywhere at once.
The regions that dry out are the subtropics — where much of the world's farmland, and a large share of its people, already live.
Where the rain leaves, the green follows: drying regions brown, and the vegetation map ends up looking like the rain map.
The same place can face more drought and more flooding at once, as a year's rain arrives in fewer, heavier bursts.
How far this goes is still undecided — the distance between the emission pathways is measured in billions of people.

Under high emissions (SSP5-8.5), far more of the world's population lives in regions where precipitation is projected to decline than under a low-emissions (SSP1-2.6) path. The gap between those futures isn't set by the climate — it's set by us.

Right here in Southern California — a Mediterranean-type climate already living on the dry edge — the models lean drier and more erratic. Where the rain falls was never an abstract question. It's home.

Data & Sources

Climate data

CMIP6 — Coupled Model Intercomparison Project Phase 6, accessed via the Pangeo Google-Cloud archive.
NCAR CESM2 — precipitation (pr) and leaf-area index (lai); historical + SSP1-2.6 / SSP2-4.5 / SSP5-8.5, ensemble member r4i1p1f1.
IPCC AR6 reference regions — Iturbide et al. (2020), Earth Syst. Sci. Data, via the regionmask package.

Projections & impacts

IPCC AR6 WG1 — Ch. 8, Water Cycle Changes (subtropical drying, high-latitude and monsoon intensification).
IPCC SRCCL — Ch. 5, Food Security (rain-fed yield losses and food-stress impacts).

All percentages are decadal means relative to the 1980–2010 baseline, area-weighted by latitude. Specific narrative figures (Amazon dry-season extension, affected-population estimates, monsoon intensification) are drawn from the IPCC assessments above; consult the cited chapters for the underlying primary literature.

Where the Rain Falls

The Rhythm We Built Civilization On

A Flourishing Baseline

Where the Rain Is Moving

A Tale Of Extremes

🌿 The Amazon Rainforest

🏜 The Sahara Desert

🌧 Mawsynram, India

📍 Find Your Region

Amazon Rainforest · Projected Change

Sahara Desert · Projected Change

Mawsynram, India · Projected Change

Region · Projected Change

When the Rain Falters, So Does Vegetation

Tropics: –11% LAI

Southern Mid‑Latitudes: –8% LAI

Northern Mid‑Latitudes: +5% LAI

The Core Takeaway: Water Moves, Farms Cannot

Tracing the Chain of Events

Why This Narrative Works

You've watched it move. Here's what moves with us.

Data & Sources

Climate data

Projections & impacts