2a:null 2b:["$","title",null,{"children":"Irrigation GHG, energy and water on formerly, intermittently and continuously irrigated lands | Karthik Ramaswamy | Observable"}] 30:T4a0,import * as topojson from "npm:topojson-client"; const metrics = (await FileAttachment("S34_county_metrics_hybrid_2015.csv").csv()).map((d) => { const o = {GEOID: d.GEOID.padStart(5, "0"), STATEFP: d.STATEFP.padStart(2, "0")}; for (const [k, v] of Object.entries(d)) if (k !== "GEOID" && k !== "STATEFP") o[k] = +v; return o; }); const summary = (await FileAttachment("S34_Table_summary_long_hybrid_2015.csv").csv()).map((d) => ({ ...d, Central: d.Central === "" ? null : +d.Central, Low: d.Low === "" ? null : +d.Low, High: d.High === "" ? null : +d.High })); const us = await fetch("https://cdn.jsdelivr.net/npm/us-atlas@3/counties-10m.json").then((r) => r.json()); const counties = topojson.feature(us, us.objects.counties); const states = topojson.mesh(us, us.objects.states, (a, b) => a !== b); const nation = topojson.feature(us, us.objects.nation); const stateNames = new Map(us.objects.states.geometries.map((d) => [d.id, d.properties.name])); const byId = new Map(metrics.map((d) => [d.GEOID, d])); const classes = ["Former", "Intermittent", "Continuous"]; // no visible output (data only) display(Object.assign(document.createElement("div"), {hidden: true}));31:Te92,// Mappable variables and map function const variables = (() => { const tot = (f, k = 1) => (d) => d[f] / k; // county total, scaled const ghg = (p, kind) => (d, s = "") => d[`${p}_${kind}_ghg${s}_t`]; // t CO₂e yr⁻¹ const share = (f) => (d) => (d[f] >= 0 ? d[f] : null); return [ {key: "F_av_ghg", label: "Formerly irrigated — avoided GHG", unit: "t CO₂e yr⁻¹", value: ghg("F", "av"), scenario: true, group: "ghg", min: 1, scheme: "YlOrRd"}, {key: "F_av_gw", label: "Formerly irrigated — avoided groundwater withdrawal", unit: "million m³ yr⁻¹", value: tot("F_av_gw_m3", 1e6), group: "gw", min: 0.01, scheme: "Blues"}, {key: "F_av_wat", label: "Formerly irrigated — avoided total withdrawal", unit: "million m³ yr⁻¹", value: tot("F_av_wat_m3", 1e6), group: "wat", min: 0.01, scheme: "Blues"}, {key: "F_av_en", label: "Formerly irrigated — avoided pumping energy", unit: "GWh yr⁻¹", value: tot("F_av_en_MWh", 1e3), group: "en", min: 0.01, scheme: "YlGn"}, {key: "I_re_ghg", label: "Intermittently irrigated — realized GHG", unit: "t CO₂e yr⁻¹", value: ghg("I", "re"), scenario: true, group: "ghg", min: 1, scheme: "YlOrRd"}, {key: "I_re_gw", label: "Intermittently irrigated — groundwater withdrawal", unit: "million m³ yr⁻¹", value: tot("I_re_gw_m3", 1e6), group: "gw", min: 0.01, scheme: "Blues"}, {key: "I_re_en", label: "Intermittently irrigated — pumping energy", unit: "GWh yr⁻¹", value: tot("I_re_en_MWh", 1e3), group: "en", min: 0.01, scheme: "YlGn"}, {key: "I_gw_pct", label: "Intermittently irrigated — groundwater share", unit: "% of withdrawals", value: share("I_gw_pct"), type: "threshold", domain: [20, 40, 60, 80], scheme: "Purples", allowZero: true}, {key: "C_re_ghg", label: "Continuously irrigated — realized GHG", unit: "t CO₂e yr⁻¹", value: ghg("C", "re"), scenario: true, group: "ghg", min: 1, scheme: "YlOrRd"}, {key: "C_gw_pct", label: "Continuously irrigated — groundwater share", unit: "% of withdrawals", value: share("C_gw_pct"), type: "threshold", domain: [20, 40, 60, 80], scheme: "Purples", allowZero: true} ]; })(); // Shared color max per group (99th percentile of current-scenario values, so outliers don't wash out the map) function sharedMax(v) { const vals = variables .filter((u) => u.group === v.group) .flatMap((u) => metrics.map((d) => u.value(d, ""))) .filter((x) => x > 0 && isFinite(x)) .sort(d3.ascending); return d3.quantile(vals, 0.99); } function mapPanel(v, s = "", {width: w = width, title} = {}) { const val = (f) => { const d = byId.get(f.id); if (!d) return null; const x = v.value(d, s); if (x == null || !isFinite(x)) return null; if (v.allowZero) return x >= 0 ? x : null; return x >= (v.min ?? 0) && x > 0 ? x : null; // grey out negligible values }; const color = v.type === "threshold" ? {type: "threshold", domain: v.domain, scheme: v.scheme, legend: true, label: v.unit} : {type: "sqrt", domain: [0, sharedMax(v)], clamp: true, scheme: v.scheme, legend: true, label: v.unit, tickFormat: "~s"}; return Plot.plot({ title, width: w, projection: "albers-usa", color, marks: [ Plot.geo(nation, {fill: "#eeeeee"}), Plot.geo(counties, Plot.centroid({ fill: val, tip: true, channels: { County: (f) => f.properties.name, State: (f) => stateNames.get(f.id.slice(0, 2)), FIPS: (f) => f.id } })), Plot.geo(states, {stroke: "white", strokeWidth: 0.6}) ] }); } // no visible output (definitions only) display(Object.assign(document.createElement("div"), {hidden: true}));32:T48a,const waterOrder = ["Realized, total", "Realized, groundwater", "Avoided, total", "Avoided, groundwater"]; display(Plot.plot({ title: "Water withdrawals by class", width, height: 300, fx: {label: null, domain: classes}, x: {axis: null, domain: waterOrder}, y: {label: "km³ yr⁻¹", grid: true}, color: {legend: true, domain: waterOrder, range: ["#08519c", "#6baed6", "#fd8d3c", "#fdd0a2"]}, marks: [ Plot.barY( summary.filter((d) => d.Group === "Water withdrawals" && classes.includes(d.Column)), {fx: "Column", x: "Metric", y: "Central", fill: "Metric", tip: true} ), Plot.ruleY([0]) ] })); display(Plot.plot({ title: "Pumping energy by class", width, height: 260, fx: {label: null, domain: classes}, x: {axis: null, domain: ["Realized", "Avoided"]}, y: {label: "TWh yr⁻¹", grid: true}, color: {legend: true, domain: ["Realized", "Avoided"], range: ["#31a354", "#fd8d3c"]}, marks: [ Plot.barY( summary.filter((d) => d.Group === "Pumping energy" && classes.includes(d.Column)), {fx: "Column", x: "Metric", y: "Central", fill: "Metric", tip: true} ), Plot.ruleY([0]) ] }));33:T418,// Summary table ("Three classes" left blank for avoided rows: not additive across classes) const summaryTable = (() => { const cols = ["Former", "Intermittent", "Continuous", "Three classes", "US total"]; const fmt = (d, unit) => { if (!d || d.Central == null) return "–"; const k = unit.startsWith("mm") || unit === "%" ? 1 : 2; const f = (x) => x.toLocaleString("en-US", {minimumFractionDigits: k, maximumFractionDigits: k}); return d.Low != null && d.High != null ? `${f(d.Central)} (${f(d.Low)}–${f(d.High)})` : f(d.Central); }; return d3.groups(summary, (d) => `${d.Group}|${d.Metric}|${d.Unit}`).map(([key, rows]) => { const [Group, Metric, Unit] = key.split("|"); const o = {Group, Metric, Unit}; for (const c of cols) { const avoided = Group.includes("avoided") || Metric.startsWith("Avoided"); o[c] = c === "Three classes" && avoided ? "–" : fmt(rows.find((r) => r.Column === c), Unit); } return o; }); })(); display(Inputs.table(summaryTable, {rows: 30, layout: "auto"}));34:T736,{ const g = (group, metric, col) => summary.find((d) => d.Group === group && d.Metric === metric && d.Column === col); const f = (d, k = 1) => (d?.Central ?? NaN).toFixed(k); const r = (d, k = 1) => `${f(d, k)} (${(d?.Low ?? NaN).toFixed(k)}–${(d?.High ?? NaN).toFixed(k)})`; const pct = (group, metric) => ((g(group, metric, "Three classes").Central / g(group, metric, "US total").Central) * 100).toFixed(0); const [cur, g50, flr] = scenOrder; const div = document.createElement("div"); div.innerHTML = `

Key numbers

Formerly irrigated lands avoid ${r(g("GHG emissions, avoided", cur, "Former"))} Mt CO₂e yr⁻¹, ${f(g("Pumping energy", "Avoided", "Former"))} TWh yr⁻¹ of pumping energy and ${f(g("Water withdrawals", "Avoided, total", "Former"))} km³ yr⁻¹ of withdrawals (${f(g("Water withdrawals", "Avoided, groundwater", "Former"))} km³ groundwater).
Intermittently irrigated lands emit ${r(g("GHG emissions, realized", cur, "Intermittent"))} Mt CO₂e yr⁻¹ and withdraw ${f(g("Water withdrawals", "Realized, total", "Intermittent"))} km³ yr⁻¹, ${f(g("Intensity per irrigated ha", "Groundwater share of withdrawals", "Intermittent"), 0)}% from groundwater.
The three classes account for ${pct("GHG emissions, realized", cur)}% of US irrigation GHG, ${pct("Pumping energy", "Realized")}% of pumping energy and ${pct("Water withdrawals", "Realized, total")}% of withdrawals.
Under 2050 grid decarbonization, avoided GHG on formerly irrigated lands falls to ${f(g("GHG emissions, avoided", g50, "Former"), 2)} Mt CO₂e yr⁻¹; the zero-energy floor is ${f(g("GHG emissions, avoided", flr, "Former"), 2)}. Water savings are unchanged.

`; display(div); }35:T175d,## Methods ### Irrigation-history classes Annual 30 m Landsat-based irrigation maps (LANID) for 1997–2025 were aligned to the Cropland Data Layer grid (Albers equal-area, 30 m). Three irrigation-history masks were derived from the 29-year record: formerly, intermittently, and continuously irrigated (irrigated in ≥ 26 of 29 years). Because the masks overlap, they were merged into one mutually exclusive class raster for accounting: - Pixels meeting both the intermittent and continuous criteria (1.40 Mha) were assigned to **continuous**. - **Formerly irrigated** pixels were required to have ≥ 3 LANID irrigated years in 1997–2022 and none in 2023–2025. Reference-former pixels irrigated in 2023–2025 (0.11 Mha) were reclassified as **intermittent**; pixels meeting neither rule (0.015 Mha) were excluded. Final class areas were 4.89 Mha (formerly), 12.59 Mha (intermittently) and 11.02 Mha (continuously irrigated). ### County × year accounting For each year 2008–2025, the class raster was combined with that year's LANID map and tabulated by county (2018 Census cartographic boundaries). Continuously and intermittently irrigated pixels were labelled *irrigated* or *non-irrigated* in each year. Formerly irrigated pixels were labelled relative to each pixel's first and last LANID irrigated years: *irrigated* (an irrigated year), *pre-irrigation* (a year before the first irrigated year), *dry-gap* (a non-irrigated year between the first and last irrigated years) or *post-irrigation* (a year after the last irrigated year, i.e. after cessation). - **Realized** quantities = irrigated area × county intensity. - **Avoided** quantities = non-irrigated area × county intensity, i.e. relative to a counterfactual of irrigating every year. For formerly irrigated land only dry-gap and post-irrigation years count; pre-irrigation years (3.2 M acre-years) are excluded. All results are mean annual values over 2008–2025 (1 acre = 0.4047 ha). ### County intensities Per-hectare intensities were computed as county totals divided by 2015 irrigated area. LANID 2015 area was used by default; where LANID detected less than half of the USGS-reported irrigated area (1,052 counties, +1.0 Mha) the USGS area was used, giving 25.7 Mha nationally (LANID 24.7 Mha; USGS 25.3 Mha). Counties with < 100 ha irrigated, missing from a source table, or with withdrawal depths > 2,500 mm yr⁻¹ (37 counties, 4.9% of withdrawals; mostly surface-water systems where withdrawals include conveyance losses) were assigned state-level intensities. The same denominator and fallback rules were applied to GHG, water and energy, and intensities were held constant across 2008–2025. ### GHG emissions County emissions came from Driscoll et al. (2024b, Supplementary Table 2): groundwater and surface-water rows for four sources — on-farm pumping (12.59 MtCO₂e yr⁻¹ nationally), elevated N₂O (2.86), interbasin transfers (1.05) and groundwater CO₂ degassing (2.40), totalling 18.90 MtCO₂e yr⁻¹. Each source has a 95% confidence interval; the uncertainty envelope reported here sums the source-specific lower and upper limits, so it is conservative. ### Water withdrawals County withdrawals came from the USGS 2015 water-use compilation (Dieter et al. 2018): crop-irrigation groundwater, surface-water and total withdrawals and consumptive use. In 13 states (1,051 counties) that do not report crop irrigation separately, total irrigation withdrawals were used; where both are reported, crop irrigation is 98.5% of the total. CONUS crop-irrigation withdrawals were 161.2 km³ yr⁻¹ (78.2 groundwater, 82.9 surface water) and consumptive use 99.2 km³ yr⁻¹. ### Pumping energy Pumping energy = withdrawal volume × county conversion factor (kWh m⁻³) following Späte et al. (2026): total pressure head (groundwater lift weighted by the groundwater share, plus irrigation-system operating pressure) divided by 367 × pump efficiency (80% electric, 30% diesel). Electric and diesel shares came from state pump-fuel statistics, with natural gas and LP gas grouped with diesel. Späte's factors were used for their 774 modelled counties (97.7% of withdrawals; reproduced exactly); the remaining counties used factors rebuilt with the same equations from Späte's well depths, USGS groundwater shares and state-median operating pressure (median ratio 0.98 to Späte where both exist; 1.7% of class energy). National pumping energy on USGS 2015 withdrawals was 36.1 TWh yr⁻¹ (22.4 TWh electricity, 13.7 TWh diesel; 130 PJ). ### Energy-system scenarios - **Current:** 2015/2018 intensities. - **2050 grid:** on-farm pumping emissions reduced 46% (Driscoll et al. 2024a); interbasin transfers unchanged. - **Zero-energy floor:** pumping and interbasin-transfer emissions set to zero, leaving N₂O and degassing. Water use and energy use are the same in all scenarios. The 46% reduction is applied uniformly and does not account for regional differences in grid carbon intensity or pump fuel. ### Validation Summing county intensity × denominator reproduced 18.73 of 18.90 MtCO₂e yr⁻¹ (99.1%) and 156.6 of 161.2 km³ yr⁻¹ (97.2%); the remainder sits in state-fallback counties. LANID 2015 irrigated area was within 2% of the USGS estimate. ### Maps Maps show county totals per class on colour scales shared across classes (square-root, capped at the 99th percentile); grey marks counties with no or negligible class area. ### Assumptions and limitations County averages are applied to every class pixel, so within-county differences in water source, well depth or pump fuel are not resolved. Source years (USGS 2015, Driscoll 2018) differ from the 2008–2025 accounting period. N₂O and degassing terms depend on fertilisation and groundwater use and may not transfer directly to rainfed crops. Avoided quantities are gross: they do not include emissions from the replacement rainfed crop or yield and land-displacement effects.36:T1894,## Results All values are mean annual 2008–2025; ranges are the conservative 95% envelope. Full values are in the summary table above. ### Irrigated area by class The three classes averaged 19.6 Mha of irrigated land per year, 76% of the 25.7 Mha irrigated nationally in 2015: 10.6 Mha continuously, 7.8 Mha intermittently and 1.2 Mha formerly irrigated (formerly irrigated land was still irrigated in some years before cessation). Non-irrigated area, the basis for avoided quantities, averaged 3.7 Mha on formerly and 4.8 Mha on intermittently irrigated land. ### GHG emissions Irrigation on continuously, intermittently and formerly irrigated lands produced 7.94 (6.43–9.80), 5.66 (4.51–7.05) and 0.96 (0.75–1.21) MtCO₂e yr⁻¹, together 14.6 (11.7–18.1) MtCO₂e yr⁻¹, or 77% of US irrigation-related emissions (18.9 MtCO₂e yr⁻¹; Driscoll et al. 2024b). Cessation of irrigation on formerly irrigated lands avoided **3.05 (2.43–3.78) MtCO₂e yr⁻¹**, about three times what these lands still emitted in their irrigated years. On-farm pumping made up 71% of the avoided emissions (2.16 Mt), followed by elevated N₂O (0.46 Mt), groundwater degassing (0.27 Mt) and interbasin transfers (0.16 Mt). Formerly irrigated land lies in counties with 11% higher emissions per irrigated hectare than continuously irrigated land (0.83 vs 0.75 tCO₂e ha⁻¹ yr⁻¹; intermittent 0.73). Avoided emissions were concentrated in southern Arizona, southern California, the Texas–Oklahoma southern Plains and the Texas Gulf Coast (panel a). Intermittently irrigated lands also avoided 3.61 (2.90–4.47) MtCO₂e yr⁻¹ in their non-irrigated years. This reflects their normal on–off pattern rather than a change in practice, so it is descriptive and is not added to the formerly irrigated total. Realized emissions on intermittent land were highest in California's Central Valley, southern Arizona, the southern High Plains and the lower Mississippi Valley (panel c). ### Pumping energy Pumping on continuously, intermittently and formerly irrigated lands required 16.2, 10.7 and 1.6 TWh yr⁻¹ of final energy, 79% of the 36.1 TWh yr⁻¹ national total. Ceasing irrigation on formerly irrigated lands avoided **4.8 TWh yr⁻¹ (17.3 PJ)**, two-thirds of it grid electricity (3.2 TWh) and one-third diesel and other fuels (1.6 TWh). Intermittently irrigated land was the most energy-intensive per unit of water (0.27 kWh m⁻³, against 0.21 on continuously and 0.22 on formerly irrigated land), reflecting its greater reliance on groundwater and on diesel pumps (44% of its pumping energy, against 37% on continuous land). Formerly irrigated land needed only slightly more energy per cubic metre than continuous land, but its pumping emissions per unit of pumping energy were higher: about 400 gCO₂e kWh⁻¹ in its irrigated years and 450 for its avoided pumping, against 315 on continuously and 355 on intermittently irrigated land. (These ratios divide Driscoll pumping emissions by Späte-based pumping energy, so they are indicative. The two Former values differ because the irrigated and avoided years are spread across different counties.) Its higher per-hectare emissions therefore reflect more carbon-intensive regional electricity more than deeper pumping. ### Water withdrawals Continuously, intermittently and formerly irrigated lands withdrew 76.6, 39.1 and 7.3 km³ yr⁻¹, together 123.0 km³ yr⁻¹ or 76% of US crop-irrigation withdrawals (161.1 km³ yr⁻¹; Dieter et al. 2018), and 80% of groundwater withdrawals (62.7 of 78.2 km³ yr⁻¹). Groundwater supplied 60% of withdrawals on intermittently irrigated land, against 48% on formerly and 47% on continuously irrigated land. Mean application depth was 721 mm yr⁻¹ on continuous, 633 on formerly and 502 on intermittently irrigated land. Cessation of irrigation on formerly irrigated lands avoided **20.5 km³ yr⁻¹ of withdrawals** (about 16.6 million acre-feet, or 13% of US crop-irrigation withdrawals), including 9.8 km³ yr⁻¹ of groundwater and 12.8 km³ yr⁻¹ of consumptive use. Avoided groundwater withdrawal was concentrated in southern Arizona, southern California, the Texas High Plains and Kansas, the Mississippi embayment and Florida (panel b). Groundwater exceeded 80% of intermittent-land withdrawals across the High Plains aquifer region, the Mississippi embayment, California's Central Valley and Florida, and was low in the Pacific Northwest and the intermountain West, which rely on surface water (panel d). ### Energy-system scenarios Under projected 2050 grid decarbonization (−46% on-farm pumping emissions), avoided emissions on formerly irrigated land fall from 3.05 to **2.06 (1.63–2.58) MtCO₂e yr⁻¹** (−32%). Realized emissions fall to 3.91 (3.07–4.97) MtCO₂e yr⁻¹ on intermittent land (−31%) and 5.59 (4.47–7.04) on continuous land (−30%); the national total falls from 18.9 to 13.1 MtCO₂e yr⁻¹. With fully decarbonized pumping energy, a non-energy floor from elevated N₂O and groundwater degassing remains: 0.73 (0.60–0.90) MtCO₂e yr⁻¹ avoided on formerly irrigated land (−76%), and 1.60 (1.24–2.09) and 2.31 (1.88–2.92) MtCO₂e yr⁻¹ emitted on intermittent and continuous land (5.3 MtCO₂e yr⁻¹ nationally). Formerly irrigated land's GHG benefit depends slightly more on the energy system than the other classes (76% energy-related, against 72%). Water savings do not change across scenarios. The 20.5 km³ yr⁻¹ avoided on formerly irrigated land holds whatever the energy mix, so as pumping decarbonizes, the environmental case for moving land out of irrigation rests increasingly on water and aquifers rather than on GHG mitigation. ### Transition potential of intermittently irrigated land Moving intermittently irrigated land permanently to rainfed production, such as bioenergy sorghum, could avoid up to **5.7 (4.5–7.1) MtCO₂e, 10.7 TWh and 39.1 km³ of withdrawals per year**, including 23.4 km³ of groundwater, at current intensities; under the 2050 grid the GHG potential falls to 3.9 (3.1–5.0) MtCO₂e yr⁻¹. These are upper bounds: they assume irrigation stops entirely and exclude emissions from the rainfed crop and any yield or land-displacement effects.37:T45b,## Data sources and references Method details are in the Methods section above; this list gives the sources. - Driscoll, A.W. et al. (2024a) *Nature Communications* 15, 675 — US irrigation pumping emissions; 2050 grid-decarbonization projection (−46%). - Driscoll, A.W. et al. (2024b) *Nature Water* 2, 837–847 — county irrigation GHG emissions by source and water source (Supplementary Table 2). - Späte, J., Mingolla, S. & Rosa, L. (2026) *Nature Communications* 17, 4504 — county pumping conversion factors, well depths and pump-fuel shares (NetZeroIrrigation repository, v1.0.0). - Dieter, C.A. et al. (2018) *Estimated use of water in the United States, county-level data for 2015* — USGS data release. - LANID annual 30 m irrigation maps, 1997–2025. - US Census Bureau 2018 cartographic boundary files (counties, cb_2018); us-atlas county TopoJSON for the web maps. **Attached data:** S34_county_metrics_hybrid_2015.csv (county totals by class) and S34_Table_summary_long_hybrid_2015.csv (summary table). The earlier density maps (per km² of county land area) are kept below for comparison.38:Te11,// Previous version (kept for comparison): densities over county land area, quantile color scales const variablesDensity = (() => { const perKm2 = (f) => (d) => d[f] / d.land_km2; const mm = (f) => (d) => (d[f] / (d.land_km2 * 1e6)) * 1000; // m3 over county land -> mm const ghg = (p, kind) => (d, s = "") => d[`${p}_${kind}_ghg${s}_t`] / d.land_km2; const share = (f) => (d) => (d[f] >= 0 ? d[f] : null); return [ {key: "F_av_ghg", label: "Formerly irrigated — avoided GHG", unit: "t CO₂e km⁻² yr⁻¹", value: ghg("F", "av"), scenario: true, scheme: "YlOrRd"}, {key: "F_av_gw", label: "Formerly irrigated — avoided groundwater withdrawal", unit: "mm yr⁻¹ over county land", value: mm("F_av_gw_m3"), scheme: "Blues"}, {key: "F_av_wat", label: "Formerly irrigated — avoided total withdrawal", unit: "mm yr⁻¹ over county land", value: mm("F_av_wat_m3"), scheme: "Blues"}, {key: "F_av_en", label: "Formerly irrigated — avoided pumping energy", unit: "MWh km⁻² yr⁻¹", value: perKm2("F_av_en_MWh"), scheme: "YlGn"}, {key: "I_re_ghg", label: "Intermittently irrigated — realized GHG", unit: "t CO₂e km⁻² yr⁻¹", value: ghg("I", "re"), scenario: true, scheme: "YlOrRd"}, {key: "I_re_gw", label: "Intermittently irrigated — groundwater withdrawal", unit: "mm yr⁻¹ over county land", value: mm("I_re_gw_m3"), scheme: "Blues"}, {key: "I_re_en", label: "Intermittently irrigated — pumping energy", unit: "MWh km⁻² yr⁻¹", value: perKm2("I_re_en_MWh"), scheme: "YlGn"}, {key: "I_gw_pct", label: "Intermittently irrigated — groundwater share", unit: "% of withdrawals", value: share("I_gw_pct"), type: "threshold", domain: [20, 40, 60, 80], scheme: "Purples", allowZero: true}, {key: "C_re_ghg", label: "Continuously irrigated — realized GHG", unit: "t CO₂e km⁻² yr⁻¹", value: ghg("C", "re"), scenario: true, scheme: "YlOrRd"}, {key: "C_gw_pct", label: "Continuously irrigated — groundwater share", unit: "% of withdrawals", value: share("C_gw_pct"), type: "threshold", domain: [20, 40, 60, 80], scheme: "Purples", allowZero: true} ]; })(); function mapPanelDensity(v, s = "", {width: w = width, title} = {}) { const val = (f) => { const d = byId.get(f.id); if (!d || !(d.land_km2 > 0)) return null; const x = v.value(d, s); if (x == null || !isFinite(x)) return null; return x > 0 || (v.allowZero && x >= 0) ? x : null; }; const color = v.type === "threshold" ? {type: "threshold", domain: v.domain, scheme: v.scheme, legend: true, label: v.unit} : {type: "quantile", n: 5, scheme: v.scheme, legend: true, label: v.unit, tickFormat: ",.3~r"}; return Plot.plot({ title, width: w, projection: "albers-usa", color, marks: [ Plot.geo(nation, {fill: "#eeeeee"}), Plot.geo(counties, Plot.centroid({ fill: val, tip: true, channels: { County: (f) => f.properties.name, State: (f) => stateNames.get(f.id.slice(0, 2)), FIPS: (f) => f.id } })), Plot.geo(states, {stroke: "white", strokeWidth: 0.6}) ] }); } { const wrap = document.createElement("div"); const h = document.createElement("h2"); h.textContent = "Previous version: densities over county land area"; const p = document.createElement("p"); p.textContent = "Kept for comparison. Values are class totals divided by total county land area (not irrigated area); each panel uses its own quantile color scale, so colors are not comparable across panels."; wrap.append(h, p); display(wrap); }39:[{"id":"2d3bf204e8d841e9fd01941e90c5985de86cb03a034af18d5a53bf7622c89f93649bf3c9fa9ccadfbb638aa44916b3548a87c0991552357901bbcee30023c63c","href":"https://static.observableusercontent.com/files/2d3bf204e8d841e9fd01941e90c5985de86cb03a034af18d5a53bf7622c89f93649bf3c9fa9ccadfbb638aa44916b3548a87c0991552357901bbcee30023c63c","name":"S34_county_metrics_hybrid_2015.csv","type":"text/csv","lastModified":1790732300393,"size":1147132},{"id":"fb768075d738d8962bae39dd18659a14d552a8e330684d037cd9b8e91a5f95ce9b7d0222b87b3cd33312d35cf6b5731a824bd15cfa2c583bcd8daa05d890669a","href":"https://static.observableusercontent.com/files/fb768075d738d8962bae39dd18659a14d552a8e330684d037cd9b8e91a5f95ce9b7d0222b87b3cd33312d35cf6b5731a824bd15cfa2c583bcd8daa05d890669a","name":"S34_Table_summary_long_hybrid_2015.csv","type":"text/csv","lastModified":1790731543399,"size":8616}] 2e:{"id":"4f139f391146635e","slug":"irrigation-ghg-energy-water-current","title":"Irrigation GHG, energy and water on formerly, intermittently and continuously irrigated lands","thumbnail":"184ad09fd8c0f70819aa74cd9aa7fb9c704ccf90406f0c3e629e7be0d1ff3f23","access_level":"public","create_time":"$D2026-09-30T01:42:35.155Z","update_time":"$D2026-09-30T14:59:59.897Z","view_time":null,"first_public_time":"$D2026-09-30T01:42:50.972Z","has_unpublished_edits":null,"fork":false,"stars":0,"starred":false,"owner":{"type":"team","id":"9736ccf33b4dd1b8","login":"karthikramaswamy","name":"Karthik Ramaswamy","avatar_url":null,"tier":"free_2026"},"version":108,"publish_version":108,"role":null,"authored":false,"authors":[{"type":"individual","id":"f4b5ce6952ea85e3","login":"karthikramaswamy","name":"Karthik Ramaswamy","avatar_url":null,"tier":null}],"members":[{"type":"team","id":"9736ccf33b4dd1b8","login":"karthikramaswamy","name":"Karthik Ramaswamy","avatar_url":null,"tier":"free_2026","role":"editor"}],"comments":[],"custom_thumbnail":false,"trashed":false,"lapsed":null,"subscribed":null,"forks":0,"collection":null,"type":"notebook","body":{"titling":"auto","title":"Irrigation GHG, energy and water on formerly, intermittently and continuously irrigated lands","cells":[{"id":1,"value":"# Irrigation GHG, energy and water on formerly, intermittently and continuously irrigated lands\n\nMean annual 2008–2025, conterminous US. County intensities from Driscoll et al. (2024b; GHG),\nSpäte et al. (2026; pumping energy) and USGS 2015 (water withdrawals), applied to mutually\nexclusive LANID irrigation-history classes. *Realized* = irrigated years; *avoided* = non-irrigated\nyears relative to irrigating every year (formerly irrigated: dry-gap and post-irrigation years only).","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":2,"value":"$30","pinned":false,"hidden":false,"mode":"ts","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":3,"value":"$31","pinned":false,"hidden":true,"mode":"ts","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":4,"value":"## Interactive county map\n\nPick a variable and, for GHG variables, an energy scenario. Values are county totals (t CO₂e, million m³ or GWh per year). Color scales are shared across classes and capped at the 99th percentile; grey = no or negligible class area; hover a county for details.","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":5,"value":"const variable = view(Inputs.select(variables, {label: \"Variable\", format: (d) => d.label, value: variables[0]}));\nconst scenario = view(Inputs.radio(\n new Map([\n [\"Current\", \"\"],\n [\"2050 grid (−46% pumping)\", \"2050\"],\n [\"Zero-energy floor (N₂O + degassing)\", \"flr\"]\n ]),\n {label: \"GHG scenario\", value: \"\"}\n));","pinned":false,"hidden":false,"mode":"ts","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":6,"value":"display(mapPanel(variable, variable.scenario ? scenario : \"\", {\n title: variable.label + (variable.scenario\n ? \" — \" + {\"\": \"current\", \"2050\": \"2050 grid\", flr: \"zero-energy floor\"}[scenario]\n : \"\")\n}));","pinned":false,"hidden":false,"mode":"ts","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":7,"value":"## Four-panel figure\n\nSame panels as the ArcGIS Pro layout (Figure X): (a, b) formerly irrigated lands, (c, d) intermittently irrigated lands.","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":8,"value":"{\n const panels = [\n [\"F_av_ghg\", \"(a) Formerly irrigated: avoided GHG\"],\n [\"F_av_gw\", \"(b) Formerly irrigated: avoided groundwater withdrawal\"],\n [\"I_re_ghg\", \"(c) Intermittently irrigated: realized GHG\"],\n [\"I_gw_pct\", \"(d) Intermittently irrigated: groundwater share\"]\n ];\n const w = Math.floor((width - 16) / 2);\n const grid = document.createElement(\"div\");\n grid.style.cssText = \"display:grid;grid-template-columns:1fr 1fr;gap:16px\";\n for (const [key, title] of panels) {\n grid.append(mapPanel(variables.find((v) => v.key === key), \"\", {width: w, title}));\n }\n display(grid);\n}\n","pinned":false,"hidden":false,"mode":"ts","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":9,"value":"## National summary by class\n\nMean annual 2008–2025. Bars = central estimate; black lines = conservative 95% envelope (sum of source-specific limits).","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":10,"value":"const ghgData = summary\n .filter((d) => d.Group.startsWith(\"GHG emissions\") && classes.includes(d.Column))\n .map((d) => ({...d, kind: d.Group.endsWith(\"realized\") ? \"Realized\" : \"Avoided\", scen: d.Metric}));\nconst scenOrder = [...new Set(ghgData.map((d) => d.scen))];\n\ndisplay(Plot.plot({\n title: \"GHG emissions by class and energy scenario\",\n width,\n height: 420,\n marginLeft: 60,\n marginRight: 80,\n fx: {label: null, domain: classes},\n fy: {label: null, domain: [\"Realized\", \"Avoided\"]},\n x: {axis: null, domain: scenOrder},\n y: {label: \"Mt CO₂e yr⁻¹\", grid: true},\n color: {legend: true, domain: scenOrder, range: [\"#b2182b\", \"#ef8a62\", \"#fddbc7\"]},\n marks: [\n Plot.barY(ghgData, {fx: \"Column\", fy: \"kind\", x: \"scen\", y: \"Central\", fill: \"scen\", tip: true}),\n Plot.ruleX(ghgData, {fx: \"Column\", fy: \"kind\", x: \"scen\", y1: \"Low\", y2: \"High\", stroke: \"#333\"}),\n Plot.ruleY([0])\n ]\n}));","pinned":false,"hidden":false,"mode":"ts","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":11,"value":"$32","pinned":false,"hidden":false,"mode":"ts","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":12,"value":"$33","pinned":false,"hidden":false,"mode":"ts","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":13,"value":"$34","pinned":false,"hidden":false,"mode":"ts","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":19,"value":"$35","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":20,"value":"$36","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":14,"value":"$37","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":15,"value":"$38","pinned":false,"hidden":false,"mode":"ts","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":16,"value":"const variableDensity = view(Inputs.select(variablesDensity, {label: \"Variable (density version)\", format: (d) => d.label, value: variablesDensity[0]}));\nconst scenarioDensity = view(Inputs.radio(\n new Map([\n [\"Current\", \"\"],\n [\"2050 grid (−46% pumping)\", \"2050\"],\n [\"Zero-energy floor (N₂O + degassing)\", \"flr\"]\n ]),\n {label: \"GHG scenario\", value: \"\"}\n));","pinned":false,"hidden":false,"mode":"ts","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":17,"value":"display(mapPanelDensity(variableDensity, variableDensity.scenario ? scenarioDensity : \"\", {\n title: \"[Density] \" + variableDensity.label + (variableDensity.scenario\n ? \" — \" + {\"\": \"current\", \"2050\": \"2050 grid\", flr: \"zero-energy floor\"}[scenarioDensity]\n : \"\")\n}));","pinned":true,"hidden":false,"mode":"ts","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":18,"value":"// Previous four-panel figure (density over county land area, own quantile scale per panel)\n{\n const panels = [\n [\"F_av_ghg\", \"(a) Formerly irrigated: avoided GHG [density]\"],\n [\"F_av_gw\", \"(b) Formerly irrigated: avoided groundwater withdrawal [density]\"],\n [\"I_re_ghg\", \"(c) Intermittently irrigated: realized GHG [density]\"],\n [\"I_gw_pct\", \"(d) Intermittently irrigated: groundwater share\"]\n ];\n const w = Math.floor((width - 16) / 2);\n const grid = document.createElement(\"div\");\n grid.style.cssText = \"display:grid;grid-template-columns:1fr 1fr;gap:16px\";\n for (const [key, title] of panels) {\n grid.append(mapPanelDensity(variablesDensity.find((v) => v.key === key), \"\", {width: w, title}));\n }\n display(grid);\n}","pinned":false,"hidden":false,"mode":"ts","author":"$undefined","summary":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"}],"files":"$W39","stdlib":"2"}} 2f:"$2e:body"