diff --git a/engine/src/modules/climate/climate.gd b/engine/src/modules/climate/climate.gd
index 087d7812..05741caf 100644
--- a/engine/src/modules/climate/climate.gd
+++ b/engine/src/modules/climate/climate.gd
@@ -1,399 +1,173 @@
 class_name Climate
-extends "res://engine/src/modules/climate/climate_base.gd"
-## Per-tile climate physics simulation. Called once per turn by TurnManager.
+extends RefCounted
+## Per-tile climate physics — thin wrapper delegating to Rust GDExtension (GdClimatePhysics).
 ##
-## Processing order each turn:
-##   1. Collect magic forcing from active spells (hook; weather.gd writes deltas)
-##   2. Update temperatures — double-buffered (reads old, writes new, swaps)
-##   3. Lake thermal moderation on adjacent tiles
-##   4. Wind moisture transport — double-buffered decay + transport + relaxation + atmospheric loss
-##   5. River moisture transport (gravity along river_edges, downhill only)
-##   6. Lake/ocean/coast evaporation into neighbours (multi-hop for ocean/coast)
-##  6b. Deep Earth Water injection (volcanoes, hot springs, high elevation)
-##   7. Precipitation (clamp excess moisture to threshold)
-##   8. Terrain quality evolution (classify_terrain + quality ladder)
-##   9. Corruption spreading and terrain flip
-##  9b. Ley residue decay
-##  9c. Ecological events (seeded stochastic perturbations)
-##  9d. Anchor decay (event-created anchors fade over time)
-##  10. Compute global stats (avg temp for UI phase label)
-##  11. Clear transient magic deltas
-##
-## Double-buffering: temperature and moisture wind use read-old/write-new
-## dictionaries to avoid order-dependent bugs when reading neighbour state.
+## The heavy simulation (temperature, moisture, wind, precipitation, terrain evolution,
+## aerosol forcing, orbital cycles, reef health, global stats) runs in native Rust.
+## This GDScript class handles Godot-side orchestration: loading params from DataLoader,
+## calling the Rust engine, and running subsystems that remain in GDScript (ley network,
+## ecological events via EventBus, magic delta clearing).
+
+const EcologicalEventsScript: GDScript = preload(
+	"res://engine/src/modules/climate/ecological_events.gd"
+)
+const AnchorDecayScript: GDScript = preload("res://engine/src/modules/climate/anchor_decay.gd")
+const LeyResidueScript: GDScript = preload("res://engine/src/modules/ley/ley_residue.gd")
+const LeyNetworkScript: GDScript = preload("res://engine/src/modules/ley/ley_network.gd")
+
+## Global average temperature — updated each turn from Rust grid state, readable by UI.
+var global_avg_temp: float = 0.5
+
+## Fraction of coast tiles permanently dead from marine extinction [0.0, 1.0].
+## Set by TurnManager from marine_harvest.ocean_dead_fraction before process_turn().
+var ocean_dead_fraction: float = 0.0
+
+var _rust: GdClimatePhysics
+var _grid: GdGridState
+var _spec_json: String = ""
+var _spec: Dictionary = {}
+var _params_loaded: bool = false
+
+## Physics capability flags from world manifest (physics_features block).
+var _physics_flags: Dictionary = {
+	"water_cycle": true,
+	"weather_events": true,
+	"ecology": true,
+	"volcanism": true,
+}
+
+
+func _ensure_rust() -> void:
+	if _params_loaded:
+		return
+
+	var params: Dictionary = DataLoader.get_climate_params()
+	if params.is_empty():
+		push_warning("Climate: climate_params.json missing — using built-in defaults")
+	_spec = DataLoader.get_climate_spec()
+	if _spec.is_empty():
+		push_warning("Climate: climate_spec.json missing — terrain transitions use built-in defaults")
+
+	var world_flags: Dictionary = DataLoader.get_physics_features()
+	if not world_flags.is_empty():
+		for key: String in world_flags:
+			_physics_flags[key] = world_flags[key]
+
+	# Collect terrain data for the Rust engine's terrain cache
+	var terrain_array: Array = DataLoader.get_all_terrains()
+
+	var params_json: String = JSON.stringify(params)
+	var terrain_json: String = JSON.stringify(terrain_array)
+	_spec_json = JSON.stringify(_spec)
+
+	_rust = GdClimatePhysics.new()
+	_rust.initialize(params_json, terrain_json, _spec_json)
+
+	_params_loaded = true
 
 
 func process_turn(game_map: RefCounted, turn: int = 0, seed: int = 42) -> void:
 	## Run the full climate simulation step for one game turn.
-	_seed = seed
-	_ensure_params()
-	_ensure_ocean_dist(game_map)
+	_ensure_rust()
 
-	_collect_magic_forcing(game_map)
-	_apply_orbital_forcing(game_map, turn)
-	_apply_aerosol_forcing(game_map)
-	_update_temperatures(game_map)
-	_update_lake_thermal_effects(game_map)
-	if _physics_flags.get("water_cycle", true):
-		_update_moisture_wind(game_map)
-		_update_moisture_rivers(game_map)
-		_update_lake_evaporation(game_map)
-		if _physics_flags.get("volcanism", true):
-			_update_deep_earth_water(game_map)
-		_update_precipitation(game_map)
-		_update_surface_runoff(game_map)
-	_check_terrain_evolution(game_map)
-	_tick_ley_residue(game_map)
+	# Sync game_map tiles into a GdGridState for the Rust engine.
+	var w: int = game_map.width
+	var h: int = game_map.height
+	if _grid == null or _grid.get_width() != w or _grid.get_height() != h:
+		_grid = GdGridState.create(w, h)
+
+	_sync_tiles_to_grid(game_map)
+	_grid.set_ocean_dead_fraction(ocean_dead_fraction)
+
+	# Run the core physics in Rust
+	_rust.process_step(_grid, turn, seed)
+
+	# Sync results back to GDScript game_map tiles
+	_sync_grid_to_tiles(game_map)
+
+	# Update global stats from Rust output
+	global_avg_temp = _grid.get_global_avg_temp()
+
+	# GDScript-side subsystems that depend on Godot autoloads
+	LeyResidueScript.tick_residue(game_map)
 	if _physics_flags.get("ecology", true):
 		EcologicalEventsScript.process_events(
 			game_map, turn, seed, _spec, DataLoader.get_ecological_events(),
 			GameState.get_max_event_tier()
 		)
 		AnchorDecayScript.process_decay(game_map, _spec)
-	_update_ley_network(game_map)
-	_compute_global_stats(game_map)
-	_clear_magic_deltas(game_map)
 
-
-# -- Step 1: Magic forcing hook --
-
-
-func _collect_magic_forcing(_game_map: RefCounted) -> void:
-	# magic_heat_delta and magic_moisture_delta are written directly by weather.gd
-	# each turn before process_turn() is called. This step is a pre-processing hook.
-	pass
-
-
-# -- Step 1a: Orbital forcing (Milankovitch-like cycles) --
-
-
-func _apply_orbital_forcing(game_map: RefCounted, turn: int) -> void:
-	## Superimpose deterministic orbital cycles onto the heat budget.
-	## Three overlapping sinusoidal cycles model obliquity, precession,
-	## and eccentricity at game timescale (1 turn = 10 years).
-	var t: float = float(turn)
-	var total_delta: float = 0.0
-	for i: int in range(1, 4):
-		var prefix: String = "orbital_cycle_%d_" % i
-		var period: float = _params.get(prefix + "period", 0.0)
-		if period <= 0.0:
-			continue
-		var amplitude: float = _params.get(prefix + "amplitude", 0.0)
-		var phase: float = _params.get(prefix + "phase", 0.0)
-		total_delta += amplitude * sin(TAU * (t / period) + phase)
-
-	if absf(total_delta) < 0.0001:
-		return
-
-	# Warm cycles increase evaporation → more moisture. The coupling factor
-	# controls how strongly temperature oscillation drives moisture oscillation.
-	var moisture_coupling: float = _params.get("orbital_moisture_coupling", 0.5)
-
-	for axial: Vector2i in game_map.tiles:
-		game_map.tiles[axial].magic_heat_delta += total_delta
-		game_map.tiles[axial].magic_moisture_delta += total_delta * moisture_coupling
-
-
-# -- Step 1b: Aerosol forcing (persistent stratospheric sulfate from volcanic/impact events) --
-
-
-func _apply_aerosol_forcing(game_map: RefCounted) -> void:
-	## Phase 0: Natural aerosol generation — desert dust, volcanic outgassing, baseline.
-	## Phase 1: apply cooling and drying to magic deltas (solar blocking + evaporation loss).
-	## Phase 2: transport aerosol downwind (double-buffered snapshot).
-	## Phase 3: decay aerosol each turn.
-	var aerosol_cfg: Dictionary = _spec.get("aerosol", {})
-	if aerosol_cfg.is_empty():
-		return
-
-	# Phase 0: Natural sources inject small aerosol each turn
-	var bg: float = _params.get("aerosol_background", 0.002)
-	var desert_rate: float = _params.get("aerosol_desert_dust", 0.005)
-	var volcano_rate: float = _params.get("aerosol_volcanic_outgas", 0.015)
-	for axial: Vector2i in game_map.tiles:
-		var tile: Variant = game_map.tiles[axial]
-		var inject: float = bg
-		if BiomeRegistry.has_tag(tile.biome_id, "is_dry"):
-			inject += desert_rate
-		elif BiomeRegistry.has_tag(tile.biome_id, "is_volcanic"):
-			inject += volcano_rate
-		tile.sulfate_aerosol = maxf(0.0, tile.get("sulfate_aerosol", 0.0) + inject)
-
-	# Short-circuit: skip processing if no aerosol exists anywhere
-	var any_aerosol: bool = false
-	for axial: Vector2i in game_map.tiles:
-		if (game_map.tiles[axial] as Object).get("sulfate_aerosol") > 0.1:
-			any_aerosol = true
-			break
-	if not any_aerosol:
-		return
-
-	var cooling_rate: float = aerosol_cfg.get("cooling_rate", 0.06)
-	var drying_rate: float = aerosol_cfg.get("drying_rate", 0.03)
-	var transport_rate: float = aerosol_cfg.get("wind_transport_rate", 0.12)
-	var decay_rate: float = aerosol_cfg.get("decay_rate", 0.05)
-
-	# Phase 1: Apply solar-blocking cooling and drying to magic deltas.
-	# Effect is capped at 100% solar blocking (aerosol > 1.0 extends duration, not intensity).
-	# City protection buildings write tile.aerosol_mitigation to scale down the effect.
-	for axial: Vector2i in game_map.tiles:
-		var tile: Variant = game_map.tiles[axial]
-		if tile.sulfate_aerosol <= 0.0:
-			continue
-		var effective: float = minf(1.0, tile.sulfate_aerosol)
-		var mitigation: float = tile.aerosol_mitigation
-		if mitigation > 0.0:
-			effective *= (1.0 - clampf(mitigation, 0.0, 1.0))
-		tile.magic_heat_delta -= effective * cooling_rate
-		tile.magic_moisture_delta -= effective * drying_rate
-
-	# Phase 2: Wind transport — double-buffered snapshot to avoid order-dependency.
-	# No cap on destination — aerosol stacks above 1.0 (more particulates = longer winter).
-	var snapshot: Dictionary = {}
-	for axial: Vector2i in game_map.tiles:
-		var tile: Variant = game_map.tiles[axial]
-		if tile.sulfate_aerosol > 0.1:
-			snapshot[axial] = tile.sulfate_aerosol
-
-	for axial: Vector2i in snapshot:
-		var tile: Variant = game_map.tiles[axial]
-		var transported: float = snapshot[axial] * transport_rate
-		var downwind: Vector2i = _downwind_pos(axial, tile.wind_direction)
-		if game_map.tiles.has(downwind):
-			game_map.tiles[downwind].sulfate_aerosol += transported
-		tile.sulfate_aerosol = maxf(0.0, tile.sulfate_aerosol - transported)
-
-	# Phase 3: Exponential decay
-	for axial: Vector2i in game_map.tiles:
-		var tile: Variant = game_map.tiles[axial]
-		if tile.sulfate_aerosol > 0.0:
-			tile.sulfate_aerosol = maxf(0.0, tile.sulfate_aerosol - decay_rate)
-
-
-# -- Step 5: River moisture transport --
-
-
-func _update_moisture_rivers(game_map: RefCounted) -> void:
-	# River transport is inherently sequential (water flows from source to mouth),
-	# so in-place update is correct — each river tile drains to its lower neighbour.
-	var transport_rate: float = _params.get(
-		"river_moisture_transport", _DEFAULTS["river_moisture_transport"]
-	)
-
-	for axial: Vector2i in game_map.tiles:
-		var tile: Variant = game_map.tiles[axial]
-		if tile.river_edges.is_empty():
-			continue
-		for edge: int in tile.river_edges:
-			var nb: Variant = game_map.tiles.get(axial + HexUtilsScript.AXIAL_DIRECTIONS[edge])
-			if nb == null or tile.elevation <= nb.elevation:
-				continue
-			var amount: float = tile.moisture * transport_rate
-			tile.moisture = clampf(tile.moisture - amount, 0.0, 1.0)
-			nb.moisture = clampf(nb.moisture + amount, 0.0, 1.0)
-
-
-# -- Step 6: Lake/ocean evaporation --
-
-
-func _update_lake_evaporation(game_map: RefCounted) -> void:
-	var base_evap: float = _params.get("evaporation_rate", _DEFAULTS["evaporation_rate"])
-	var max_hops: int = int(
-		_params.get("ocean_evaporation_hops", _DEFAULTS["ocean_evaporation_hops"])
-	)
-	var hop_decay: float = _params.get(
-		"ocean_evaporation_hop_decay", _DEFAULTS["ocean_evaporation_hop_decay"]
-	)
-	var rain_shadow_block: float = _params.get(
-		"mountain_rain_shadow_block", _DEFAULTS["mountain_rain_shadow_block"]
-	)
-	# Biological pump failure: dead ocean reduces evaporation → inland forests dry out.
-	# Formula from OCEAN.md: evap *= (1 - (fraction - 0.25) * 2) when fraction > 0.25.
-	var evap_rate: float = base_evap
-	if ocean_dead_fraction > 0.25:
-		evap_rate = base_evap * maxf(0.0, 1.0 - (ocean_dead_fraction - 0.25) * 2.0)
-
-	for axial: Vector2i in game_map.tiles:
-		var tile: Variant = game_map.tiles[axial]
-		var tid: String = tile.biome_id
-		if not BiomeRegistry.has_tag(tid, "is_water"):
-			continue
-		# Only evaporate if liquid water is actually present
-		if tile.surface_water <= 0.0:
-			continue
-
-		var evap: float = tile.temperature * evap_rate * minf(1.0, tile.surface_water)
-
-		if tid == "lake":
-			# Lakes inject to all 6 neighbours equally
-			var share: float = evap / 6.0
-			for nb_pos: Vector2i in HexUtilsScript.get_neighbors(axial):
-				var nb: Variant = game_map.tiles.get(nb_pos)
-				if nb != null:
-					nb.moisture = clampf(nb.moisture + share, 0.0, 1.0)
-		else:
-			# Ocean/coast: inject along downwind chain (multi-hop with decay).
-			# Hop 1 = full strength, hop 2 = hop_decay, hop 3 = hop_decay^2, etc.
-			# Stop at mountains (rain shadow), water tiles (no double-injection), or map edge.
-			var hop_pos: Vector2i = axial
-			var hop_strength: float = 1.0
-			var wind_dir: int = tile.wind_direction
-			for _hop_i: int in max_hops:
-				hop_pos = hop_pos + HexUtilsScript.AXIAL_DIRECTIONS[wind_dir]
-				var hop_tile: Variant = game_map.tiles.get(hop_pos)
-				if hop_tile == null:
-					break
-				var hop_tid: String = hop_tile.biome_id
-				# Stop if we hit another water tile (no double-injection)
-				if BiomeRegistry.has_tag(hop_tid, "is_water"):
-					break
-				# Mountains block most moisture (rain shadow)
-				if BiomeRegistry.has_tag(hop_tid, "is_elevated"):
-					hop_strength *= (1.0 - rain_shadow_block)
-				hop_tile.moisture = clampf(hop_tile.moisture + evap * hop_strength, 0.0, 1.0)
-				hop_strength *= hop_decay
-				# Follow the hop tile's own wind direction for subsequent hops
-				wind_dir = hop_tile.wind_direction
-
-
-# -- Step 6b: Deep Earth Water (volcanic outgassing) --
-
-
-func _update_deep_earth_water(game_map: RefCounted) -> void:
-	## Mantle degassing: volcanoes, hot springs, and high-elevation tiles inject moisture.
-	## Models ringwoodite water release through the crust — the mechanism that maintains
-	## Earth's ocean volume over geological time despite atmospheric hydrogen escape.
-	var dew: Dictionary = _params.get("deep_earth_water", _DEW_DEFAULTS)
-	var vol_self: float = dew.get("volcano_self", _DEW_DEFAULTS["volcano_self"])
-	var vol_nb: float = dew.get("volcano_neighbor", _DEW_DEFAULTS["volcano_neighbor"])
-	var hs_self: float = dew.get("hot_spring_self", _DEW_DEFAULTS["hot_spring_self"])
-	var hs_nb: float = dew.get("hot_spring_neighbor", _DEW_DEFAULTS["hot_spring_neighbor"])
-	var hs_max_temp: float = dew.get("hot_spring_max_temperature", _DEW_DEFAULTS["hot_spring_max_temperature"])
-	var elev_self: float = dew.get("high_elevation_self", _DEW_DEFAULTS["high_elevation_self"])
-	var elev_thresh: float = dew.get(
-		"high_elevation_threshold", _DEW_DEFAULTS["high_elevation_threshold"]
-	)
-
-	for axial: Vector2i in game_map.tiles:
-		var tile: Variant = game_map.tiles[axial]
-
-		if BiomeRegistry.has_tag(tile.biome_id, "is_volcanic"):
-			tile.moisture = clampf(tile.moisture + vol_self, 0.0, 1.0)
-			for nb_pos: Vector2i in HexUtilsScript.get_neighbors(axial):
-				var nb: Variant = game_map.tiles.get(nb_pos)
-				if nb != null:
-					nb.moisture = clampf(nb.moisture + vol_nb, 0.0, 1.0)
-
-		elif tile.river_source_type == "hot_spring" and tile.temperature <= hs_max_temp:
-			tile.moisture = clampf(tile.moisture + hs_self, 0.0, 1.0)
-			for nb_pos: Vector2i in HexUtilsScript.get_neighbors(axial):
-				var nb: Variant = game_map.tiles.get(nb_pos)
-				if nb != null:
-					nb.moisture = clampf(nb.moisture + hs_nb, 0.0, 1.0)
-
-		elif tile.elevation >= elev_thresh:
-			tile.moisture = clampf(tile.moisture + elev_self, 0.0, 1.0)
-
-
-# -- Step 7: Precipitation --
-
-
-func _update_precipitation(game_map: RefCounted) -> void:
-	var threshold: float = _params.get(
-		"precipitation_threshold", _DEFAULTS["precipitation_threshold"]
-	)
-	var h: int = game_map.height
-	var lat_spec: Dictionary = _spec.get("precipitation_latitude", {})
-	var polar_band: float = lat_spec.get("polar_drying", {}).get("band_pct", 0.15)
-	var polar_rate: float = lat_spec.get("polar_drying", {}).get("rate_per_turn", 0.008)
-	var sub_center: float = lat_spec.get("subtropical_drying", {}).get("center_pct", 0.30)
-	var sub_half: float = lat_spec.get("subtropical_drying", {}).get("half_width", 0.15)
-	var sub_rate: float = lat_spec.get("subtropical_drying", {}).get("rate_per_turn", 0.013)
-
-	for axial: Vector2i in game_map.tiles:
-		var tile: Variant = game_map.tiles[axial]
-		if tile.moisture > threshold:
-			var runoff: float = tile.moisture - threshold
-			tile.moisture = threshold
-			tile.surface_water += runoff  # excess moisture precipitates as surface water
-
-		# Latitude-dependent moisture adjustment — models Hadley cell circulation.
-		# Polar regions are dry (cold air holds less moisture).
-		# Subtropical high-pressure belt (~30° latitude) suppresses moisture.
-		var offset: Vector2i = HexUtilsScript.axial_to_offset(axial)
-		var row: int = clampi(offset.y, 0, h - 1)
-		var frac: float = float(row) / float(h)
-		var norm_frac: float = frac if frac <= 0.5 else 1.0 - frac  # 0=pole, 0.5=equator
-
-		if norm_frac < polar_band:
-			tile.moisture = maxf(0.0, tile.moisture - polar_rate)
-
-		if norm_frac > polar_band and norm_frac < sub_center + sub_half:
-			var dry_strength: float = maxf(0.0, 1.0 - absf(norm_frac - sub_center) / sub_half)
-			tile.moisture = maxf(0.05, tile.moisture - sub_rate * dry_strength)
-
-
-# -- Step 9b: Ley residue decay --
-
-
-func _tick_ley_residue(game_map: RefCounted) -> void:
-	LeyResidueScript.tick_residue(game_map)
-
-
-func _update_ley_network(game_map: RefCounted) -> void:
-	## Build resonance/disruption edges between wonder anchors and apply effects.
 	var edges: Array = LeyNetworkScript.build_network(game_map, _spec)
 	LeyNetworkScript.apply_ley_effects(game_map, edges, _spec)
 	EventBus.ley_network_updated.emit(edges)
 
 
-# -- Step 10: Global stats --
+# Tile access uses Variant because game_map.tiles is a Dictionary[Vector2i, RefCounted]
+# and tile objects are class_name types that cannot be typed across autoload boundary.
+# See CLAUDE.md "Signal Parameters" — Variant is required here.
 
 
-func _compute_global_stats(game_map: RefCounted) -> void:
-	var total: float = 0.0
-	var count: int = 0
+func _sync_tiles_to_grid(game_map: RefCounted) -> void:
+	## Push GDScript tile state into the Rust GdGridState before physics.
 	for axial: Vector2i in game_map.tiles:
-		var tile: Variant = game_map.tiles[axial]
-		if tile.biome_id != "ocean":
-			total += tile.temperature
-			count += 1
-	global_avg_temp = total / float(count) if count > 0 else 0.5
+		# Tile access returns RefCounted subclass — Variant required at autoload boundary
+		var tile: RefCounted = game_map.tiles[axial] as RefCounted
+		var col: int = tile.get("col") as int
+		var row: int = tile.get("row") as int
+		var d: Dictionary = {
+			"temperature": tile.get("temperature"),
+			"moisture": tile.get("moisture"),
+			"elevation": tile.get("elevation"),
+			"biome_id": tile.get("biome_id"),
+			"wind_direction": tile.get("wind_direction"),
+			"wind_speed": tile.get("wind_speed"),
+			"sulfate_aerosol": tile.get("sulfate_aerosol"),
+			"quality": tile.get("quality"),
+			"quality_progress": tile.get("quality_progress"),
+			"original_biome_id": tile.get("original_biome_id"),
+			"ley_line_count": tile.get("ley_line_count"),
+			"ley_school": tile.get("ley_school"),
+			"reef_health": tile.get("reef_health"),
+			"magic_heat_delta": tile.get("magic_heat_delta"),
+			"magic_moisture_delta": tile.get("magic_moisture_delta"),
+			"is_natural_wonder": tile.get("is_natural_wonder"),
+			"wonder_anchor_strength": tile.get("wonder_anchor_strength"),
+			"wonder_tier": tile.get("wonder_tier"),
+			"canopy_cover": tile.get("canopy_cover"),
+			"undergrowth": tile.get("undergrowth"),
+			"fungi_network": tile.get("fungi_network"),
+			"surface_water": tile.get("surface_water"),
+			"river_source_type": tile.get("river_source_type"),
+			"is_coastal": tile.get("is_coastal"),
+			"aerosol_mitigation": tile.get("aerosol_mitigation"),
+		}
+		_grid.set_tile_dict(col, row, d)
 
-	# Reef health on coast tiles — coral bleaching from high SST
-	var reef_spec: Dictionary = _spec.get("reef_bleaching", {})
-	var bleach_thresh: float = reef_spec.get("bleach_temp_threshold", 0.75)
-	var damage_rate: float = reef_spec.get("damage_rate_per_turn", 0.01)
-	var recovery_rate: float = reef_spec.get("recovery_rate_per_turn", 0.005)
-	var dead_thresh: float = reef_spec.get("dead_threshold", 0.3)
-	var coast_count: int = 0
-	var dead_count: int = 0
+
+func _sync_grid_to_tiles(game_map: RefCounted) -> void:
+	## Pull Rust physics results back into GDScript tiles after physics.
 	for axial: Vector2i in game_map.tiles:
-		var tile: Variant = game_map.tiles[axial]
-		if tile.biome_id != "coast":
+		var tile: RefCounted = game_map.tiles[axial] as RefCounted
+		var col: int = tile.get("col") as int
+		var row: int = tile.get("row") as int
+		var d: Dictionary = _grid.get_tile_dict(col, row)
+		if d.is_empty():
 			continue
-		coast_count += 1
-		if tile.temperature > bleach_thresh:
-			tile.reef_health = maxf(0.0, tile.reef_health - damage_rate)
-		else:
-			tile.reef_health = minf(1.0, tile.reef_health + recovery_rate)
-		if tile.reef_health < dead_thresh:
-			dead_count += 1
-	if coast_count > 0:
-		ocean_dead_fraction = float(dead_count) / float(coast_count)
-
-
-# -- Step 11: Clear transient magic deltas --
-
-
-func _clear_magic_deltas(game_map: RefCounted) -> void:
-	for axial: Vector2i in game_map.tiles:
-		var tile: Variant = game_map.tiles[axial]
-		tile.magic_heat_delta = 0.0
-		tile.magic_moisture_delta = 0.0
-
-
-# -- UI helper --
+		tile.set("temperature", d.get("temperature", tile.get("temperature")))
+		tile.set("moisture", d.get("moisture", tile.get("moisture")))
+		tile.set("biome_id", d.get("biome_id", tile.get("biome_id")))
+		tile.set("sulfate_aerosol", d.get("sulfate_aerosol", 0.0))
+		tile.set("quality", d.get("quality", tile.get("quality")))
+		tile.set("quality_progress", d.get("quality_progress", tile.get("quality_progress")))
+		tile.set("original_biome_id", d.get("original_biome_id", tile.get("original_biome_id")))
+		tile.set("reef_health", d.get("reef_health", tile.get("reef_health")))
+		tile.set("magic_heat_delta", d.get("magic_heat_delta", 0.0))
+		tile.set("magic_moisture_delta", d.get("magic_moisture_delta", 0.0))
+		tile.set("surface_water", d.get("surface_water", tile.get("surface_water")))
+		tile.set("canopy_cover", d.get("canopy_cover", 0.0))
+		tile.set("undergrowth", d.get("undergrowth", 0.0))
+		tile.set("fungi_network", d.get("fungi_network", 0.0))
+		tile.set("habitat_suitability", d.get("habitat_suitability", 0.0))
 
 
 func get_phase_label() -> String:
@@ -404,68 +178,3 @@ func get_phase_label() -> String:
 		if global_avg_temp < THRESHOLDS[i]:
 			return LABELS[i]
 	return LABELS[LABELS.size() - 1]
-
-
-# -- Internal helpers --
-
-
-func _ensure_params() -> void:
-	if _params_loaded:
-		return
-	_params = DataLoader.get_climate_params()
-	if _params.is_empty():
-		push_warning("Climate: climate_params.json missing — using built-in defaults")
-		_params = _DEFAULTS.duplicate()
-	_spec = DataLoader.get_climate_spec()
-	if _spec.is_empty():
-		push_warning(
-			"Climate: climate_spec.json missing — terrain transitions use built-in defaults"
-		)
-	var world_flags: Dictionary = DataLoader.get_physics_features()
-	if not world_flags.is_empty():
-		for key: String in world_flags:
-			_physics_flags[key] = world_flags[key]
-
-	_params_loaded = true
-
-
-func _ensure_ocean_dist(game_map: RefCounted) -> void:
-	## Build ocean proximity cache via BFS if not yet computed.
-	## Invalidated by terrain_transformed signal (terrain flips can create/remove water).
-	if _ocean_dist_valid:
-		return
-	_ocean_dist_cache.clear()
-
-	# Seed BFS from all water tiles (distance 0)
-	var queue: Array[Vector2i] = []
-	for axial: Vector2i in game_map.tiles:
-		var tid: String = game_map.tiles[axial].biome_id
-		if BiomeRegistry.has_tag(tid, "is_water"):
-			_ocean_dist_cache[axial] = 0
-			queue.append(axial)
-
-	# BFS outward — cap at 20 hexes (beyond this, factor bottoms out at floor anyway)
-	var head: int = 0
-	while head < queue.size():
-		var pos: Vector2i = queue[head]
-		head += 1
-		var dist: int = _ocean_dist_cache[pos]
-		if dist >= 20:
-			continue
-		for nb_pos: Vector2i in HexUtilsScript.get_neighbors(pos):
-			if not game_map.tiles.has(nb_pos):
-				continue
-			if _ocean_dist_cache.has(nb_pos):
-				continue
-			_ocean_dist_cache[nb_pos] = dist + 1
-			queue.append(nb_pos)
-
-	_ocean_dist_valid = true
-
-	# Listen for terrain changes that might invalidate the cache
-	if not EventBus.terrain_transformed.is_connected(_on_terrain_transformed):
-		EventBus.terrain_transformed.connect(_on_terrain_transformed)
-
-
-func _on_terrain_transformed(_tile: Variant, _old_type: String, _new_type: String) -> void:
-	_ocean_dist_valid = false
diff --git a/engine/src/modules/climate/climate_base.gd b/engine/src/modules/climate/climate_base.gd
deleted file mode 100644
index 827b357d..00000000
--- a/engine/src/modules/climate/climate_base.gd
+++ /dev/null
@@ -1,351 +0,0 @@
-class_name ClimateBase
-extends RefCounted
-## Per-tile climate physics — base class containing heavy simulation step functions.
-## Inherited by Climate which adds the orchestration layer.
-
-const MapGeneratorScript: GDScript = preload("res://engine/src/generation/map_generator.gd")
-const HexUtilsScript: GDScript = preload("res://engine/src/map/hex_utils.gd")
-const TerrainAffinityScript: GDScript = preload("res://engine/src/core/terrain_affinity.gd")
-const LeyResidueScript: GDScript = preload("res://engine/src/modules/ley/ley_residue.gd")
-const ClimateSpecEvalScript: GDScript = preload(
-	"res://engine/src/modules/climate/climate_spec_eval.gd"
-)
-const EcologicalEventsScript: GDScript = preload(
-	"res://engine/src/modules/climate/ecological_events.gd"
-)
-const AnchorDecayScript: GDScript = preload("res://engine/src/modules/climate/anchor_decay.gd")
-const LeyNetworkScript: GDScript = preload("res://engine/src/modules/ley/ley_network.gd")
-
-# Fallback defaults — used only when climate_params.json absent (logs warning)
-const _DEFAULTS: Dictionary = {
-	"wind_conductivity": 0.1,
-	"energy_scale": 0.005,
-	"equilibrium_relaxation": 0.08,
-	"evaporation_rate": 0.05,
-	"moisture_transport": 0.15,
-	"precipitation_threshold": 0.7,
-	"moisture_decay": 0.995,
-	"ocean_evaporation_hops": 4,
-	"ocean_evaporation_hop_decay": 0.5,
-	"atmospheric_loss_rate": 0.0003,
-	"quality_up_threshold": 10,
-	"quality_down_threshold": 5,
-	"lake_thermal_conductivity": 0.05,
-	"river_moisture_transport": 0.075,
-	"mountain_rain_shadow_block": 0.9,
-	"solar_min": 0.05,
-	"solar_max": 0.70,
-}
-
-const _DEW_DEFAULTS: Dictionary = {
-	"volcano_self": 0.008,
-	"volcano_neighbor": 0.004,
-	"hot_spring_self": 0.005,
-	"hot_spring_neighbor": 0.002,
-	"hot_spring_max_temperature": 0.60,
-	"high_elevation_self": 0.002,
-	"high_elevation_threshold": 0.8,
-}
-
-## Global average temperature — updated each turn, readable by UI
-var global_avg_temp: float = 0.5
-
-## Fraction of coast tiles permanently dead from marine extinction [0.0, 1.0].
-## Set by TurnManager from marine_harvest.ocean_dead_fraction before process_turn().
-## Scales ocean evaporation down — biological pump failure reduces moisture transport inland.
-var ocean_dead_fraction: float = 0.0
-
-## Random seed passed from TurnManager — used by stochastic subsystems.
-var _seed: int = 42
-
-# Climate params from DataLoader — loaded once, then cached
-var _params: Dictionary = {}
-var _spec: Dictionary = {}
-var _params_loaded: bool = false
-# Physics capability flags from world manifest (physics_features block).
-# Defaults to all-enabled so Earth worlds without the field keep working.
-var _physics_flags: Dictionary = {
-	"water_cycle": true,
-	"weather_events": true,
-	"ecology": true,
-	"volcanism": true,
-}
-
-# Per-terrain data cache (albedo, evapotranspiration) keyed by biome_id string
-var _terrain_cache: Dictionary = {}
-
-# Ocean proximity cache: axial → int (hex distance to nearest water tile).
-# Computed once via BFS on first use, invalidated when terrain transforms.
-var _ocean_dist_cache: Dictionary = {}  # axial → int
-var _ocean_dist_valid: bool = false
-
-
-# -- Step 2: Temperature update (double-buffered) --
-
-
-func _update_temperatures(game_map: RefCounted) -> void:
-	var conductivity: float = _params.get("wind_conductivity", _DEFAULTS["wind_conductivity"])
-	var energy_scale: float = _params.get("energy_scale", _DEFAULTS["energy_scale"])
-	var relaxation: float = _params.get(
-		"equilibrium_relaxation", _DEFAULTS["equilibrium_relaxation"]
-	)
-	var h: int = game_map.height
-	var center_row: float = float(h) / 2.0
-
-	# Pre-compute solar baseline per row — same value for every tile in a row
-	var solar_by_row: Dictionary = {}
-	for row: int in h:
-		solar_by_row[row] = _solar_by_latitude(row, center_row)
-
-	# Snapshot current temperatures into a read buffer — prevents stale reads
-	# when upwind tiles have already been updated in this same pass.
-	var old_temp: Dictionary = {}  # axial → float
-	for axial: Vector2i in game_map.tiles:
-		old_temp[axial] = game_map.tiles[axial].temperature
-
-	# Compute new temperatures from old values only, write into new_temp buffer
-	var new_temp: Dictionary = {}  # axial → float
-	for axial: Vector2i in game_map.tiles:
-		var tile: Variant = game_map.tiles[axial]
-		var offset: Vector2i = HexUtilsScript.axial_to_offset(axial)
-		var solar: float = solar_by_row[clampi(offset.y, 0, h - 1)]
-		var current_temp: float = old_temp[axial]
-
-		var terrain_data: Dictionary = _get_terrain_data(tile.biome_id)
-		var albedo: float = terrain_data.get("albedo", 0.4)
-		var net_solar: float = solar * (1.0 - albedo) * energy_scale
-
-		# Wind transport: read upwind tile temperature from old snapshot
-		var wind_transport: float = 0.0
-		var upwind_pos: Vector2i = _upwind_pos(axial, tile.wind_direction)
-		if old_temp.has(upwind_pos):
-			wind_transport = (
-				(old_temp[upwind_pos] - current_temp) * tile.wind_speed * conductivity
-			)
-
-		var relax: float = (solar - current_temp) * relaxation
-		new_temp[axial] = clampf(
-			current_temp + net_solar + wind_transport + relax + tile.magic_heat_delta, 0.0, 1.0
-		)
-
-	# Swap: write buffered results back to tiles
-	for axial: Vector2i in new_temp:
-		game_map.tiles[axial].temperature = new_temp[axial]
-
-
-# -- Step 3: Lake thermal moderation --
-
-
-func _update_lake_thermal_effects(game_map: RefCounted) -> void:
-	# Lakes moderate adjacent land tiles toward lake temperature.
-	# Read lake temps from post-step-2 values — moderation is a secondary effect
-	# and doesn't require double-buffering (lakes don't read each other here).
-	var conductivity: float = _params.get(
-		"lake_thermal_conductivity", _DEFAULTS["lake_thermal_conductivity"]
-	)
-
-	for axial: Vector2i in game_map.tiles:
-		var tile: Variant = game_map.tiles[axial]
-		if tile.biome_id != "lake":
-			continue
-		var lake_temp: float = tile.temperature
-		for nb_pos: Vector2i in HexUtilsScript.get_neighbors(axial):
-			var nb: Variant = game_map.tiles.get(nb_pos)
-			if nb == null:
-				continue
-			var diff: float = lake_temp - nb.temperature
-			nb.temperature = clampf(nb.temperature + diff * conductivity, 0.0, 1.0)
-
-
-# -- Step 4: Wind moisture transport (double-buffered) --
-
-
-func _update_moisture_wind(game_map: RefCounted) -> void:
-	var transport_rate: float = _params.get("moisture_transport", _DEFAULTS["moisture_transport"])
-	var decay: float = _params.get("moisture_decay", _DEFAULTS["moisture_decay"])
-	var rain_shadow_block: float = _params.get(
-		"mountain_rain_shadow_block", _DEFAULTS["mountain_rain_shadow_block"]
-	)
-	var atmo_loss: float = _params.get("atmospheric_loss_rate", _DEFAULTS["atmospheric_loss_rate"])
-
-	# Snapshot moisture before decay so all tiles decay from the same baseline
-	var old_moisture: Dictionary = {}  # axial → float
-	for axial: Vector2i in game_map.tiles:
-		old_moisture[axial] = game_map.tiles[axial].moisture * decay
-
-	# Compute new moisture from decayed old values + upwind transport.
-	# Reading old_moisture[upwind] avoids stale-write order dependence.
-	var new_moisture: Dictionary = {}  # axial → float
-	for axial: Vector2i in game_map.tiles:
-		var tile: Variant = game_map.tiles[axial]
-		var current: float = old_moisture[axial]
-
-		# Upwind moisture transport
-		var upwind_pos: Vector2i = _upwind_pos(axial, tile.wind_direction)
-		var transported: float = 0.0
-		if old_moisture.has(upwind_pos):
-			var upwind_tile: Variant = game_map.tiles.get(upwind_pos)
-			var upwind_is_mountain: bool = (
-				upwind_tile != null and BiomeRegistry.has_tag(upwind_tile.biome_id, "is_elevated")
-			)
-			var block: float = rain_shadow_block if upwind_is_mountain else 0.0
-			transported = (
-				old_moisture[upwind_pos] * tile.wind_speed * transport_rate * (1.0 - block)
-			)
-
-		# Evapotranspiration and magic forcing are per-tile local effects — safe to add here
-		var terrain_data: Dictionary = _get_terrain_data(tile.biome_id)
-		var evapotrans: float = terrain_data.get("evapotranspiration", 0.0)
-
-		# Atmospheric loss to space — Jeans escape (temperature-scaled).
-		# Balanced by volcanic outgassing (deep_earth_water step). No baseline injection needed.
-		var space_loss: float = current * atmo_loss * tile.temperature
-
-		new_moisture[axial] = clampf(
-			(
-				current
-				+ transported
-				+ evapotrans
-				- space_loss
-				+ tile.magic_moisture_delta
-			),
-			0.0,
-			1.0
-		)
-
-	# Swap
-	for axial: Vector2i in new_moisture:
-		game_map.tiles[axial].moisture = new_moisture[axial]
-
-
-# -- Step 7b: Surface runoff — move surface water downhill into ocean --
-
-
-func _update_surface_runoff(game_map: RefCounted) -> void:
-	## Surface water flows downhill along river_edges into ocean-substrate tiles.
-	## Draining into ocean substrate adds to the planetary water reservoir (drives sea_level).
-	## No downhill neighbour → water pools (lake formation).
-	var runoff_rate: float = _params.get("surface_runoff_rate", 0.3)
-	var ocean_substrates: Array[String] = ["deep_water", "shallow_water"]
-
-	for axial: Vector2i in game_map.tiles:
-		var tile: Variant = game_map.tiles[axial]
-		if tile.surface_water <= 0.0:
-			continue
-
-		# Find the steepest downhill river_edge neighbor
-		var best_nb: Variant = null
-		var best_drop: float = 0.0
-		for edge: int in tile.river_edges:
-			var nb_pos: Vector2i = axial + HexUtilsScript.AXIAL_DIRECTIONS[edge]
-			var nb: Variant = game_map.tiles.get(nb_pos)
-			if nb == null:
-				continue
-			var drop: float = tile.elevation - nb.elevation
-			if drop > best_drop:
-				best_drop = drop
-				best_nb = nb
-
-		if best_nb == null:
-			continue  # no downhill neighbor — water pools here
-
-		var flow: float = tile.surface_water * runoff_rate
-		tile.surface_water -= flow
-		if best_nb.substrate_id in ocean_substrates:
-			game_map.total_ocean_water += flow
-		else:
-			best_nb.surface_water += flow
-
-
-# -- Step 8: Terrain quality evolution --
-
-
-func _check_terrain_evolution(game_map: RefCounted) -> void:
-	var up_thresh: int = int(_params.get("quality_up_threshold", _DEFAULTS["quality_up_threshold"]))
-	var down_thresh: int = int(_params.get("quality_down_threshold", _DEFAULTS["quality_down_threshold"]))
-
-	for axial: Vector2i in game_map.tiles:
-		var tile: Variant = game_map.tiles[axial]
-		var tid: String = tile.biome_id
-
-		if tile.is_natural_wonder:
-			continue
-
-		# Water freezing/thawing
-		var freeze_temp: float = _params.get("water_freeze_threshold", 0.12)
-		var thaw_temp: float = freeze_temp + 0.03
-		var is_water: bool = BiomeRegistry.has_tag(tid, "is_water")
-		if is_water:
-			if tile.temperature < freeze_temp:
-				tile.original_biome_id = tid
-				tile.biome_id = "ice"
-				tile.quality = 1
-				tile.quality_progress = 0
-			continue
-		if BiomeRegistry.has_tag(tid, "is_frozen"):
-			if tile.temperature > thaw_temp and tile.original_biome_id != "":
-				tile.biome_id = tile.original_biome_id
-				tile.original_biome_id = ""
-				tile.quality = 1
-				tile.quality_progress = 0
-			continue
-
-		if BiomeRegistry.has_tag(tid, "is_volcanic"):
-			continue
-
-		var ideal: String = _ideal_terrain(tile)
-
-		if ideal == tid:
-			tile.quality_progress += 1
-			if tile.quality_progress >= up_thresh:
-				tile.quality_progress = 0
-				if tile.quality < 5:
-					tile.quality += 1
-		else:
-			tile.quality_progress -= 1
-			if tile.quality_progress <= -down_thresh:
-				tile.quality_progress = 0
-				if tile.quality > 1:
-					tile.quality -= 1
-				else:
-					tile.biome_id = ideal
-					tile.quality = 1
-					tile.quality_progress = 0
-
-
-# -- Internal helpers --
-
-
-func _get_terrain_data(biome_id: String) -> Dictionary:
-	if not _terrain_cache.has(biome_id):
-		_terrain_cache[biome_id] = DataLoader.get_terrain(biome_id)
-	return _terrain_cache[biome_id]
-
-
-func _solar_by_latitude(row: int, center_row: float) -> float:
-	## Solar input at a given map row, clamped to habitable range.
-	## Raw latitude factor: 1.0 at equator, 0.0 at poles.
-	## Mapped via solar_min/solar_max params to produce stable equilibrium
-	## temperatures that support reef survival and biome diversity.
-	var raw: float = 1.0 - absf((float(row) - center_row) / center_row)
-	var solar_min: float = _params.get("solar_min", _DEFAULTS.get("solar_min", 0.05))
-	var solar_max: float = _params.get("solar_max", _DEFAULTS.get("solar_max", 0.70))
-	return solar_min + (solar_max - solar_min) * raw
-
-
-func _upwind_pos(axial: Vector2i, wind_dir: int) -> Vector2i:
-	## Return the axial position that wind blows FROM (opposite to wind_direction).
-	return axial + HexUtilsScript.AXIAL_DIRECTIONS[(wind_dir + 3) % 6]
-
-
-func _downwind_pos(axial: Vector2i, wind_dir: int) -> Vector2i:
-	## Return the axial position that wind blows TOWARD (same as wind_direction).
-	return axial + HexUtilsScript.AXIAL_DIRECTIONS[wind_dir % 6]
-
-
-func _ideal_terrain(tile: Variant) -> String:
-	return ClimateSpecEvalScript.ideal_terrain(tile, _spec)
-
-
-func _ley_channeling_mult(nb: Variant) -> float:
-	return ClimateSpecEvalScript.ley_channeling_mult(nb, _spec)
diff --git a/engine/src/modules/climate/climate_spec_eval.gd b/engine/src/modules/climate/climate_spec_eval.gd
index 4fa15f04..f881491a 100644
--- a/engine/src/modules/climate/climate_spec_eval.gd
+++ b/engine/src/modules/climate/climate_spec_eval.gd
@@ -1,112 +1,34 @@
 class_name ClimateSpecEval
 extends RefCounted
 ## Evaluates terrain transition rules and ley channeling multipliers from climate_spec.json.
-## Pure logic — no side effects, no state mutation. Used by Climate and the transpiler.
-
-const MapGeneratorScript: GDScript = preload("res://engine/src/generation/map_generator.gd")
-const BiomeClassifierScript = preload("res://engine/src/models/world/biome_classifier.gd")
+## Thin wrapper delegating to Rust GDExtension (GdClimateSpecEval).
 
 
-static func ideal_terrain(tile: Variant, spec: Dictionary) -> String:
-	## Determine the climate-ideal terrain type for a tile. Reads transition rules
-	## from climate_spec.json terrain_transitions. If a terrain has no spec entry,
-	## falls back to BiomeClassifier.classify().
-	var tid: String = tile.biome_id
-	var temp: float = tile.temperature
-	var moist: float = tile.moisture
-	var canopy: float = tile.get("canopy_cover", 0.0)
-
-	var transitions: Dictionary = spec.get("terrain_transitions", {})
-	var rules: Array = transitions.get(tid, [])
-	if rules.is_empty():
-		return BiomeClassifierScript.classify(tile)
-
-	for rule: Variant in rules:
-		if not rule is Dictionary:
-			continue
-		if eval_condition(rule.get("condition", ""), temp, moist, tile.elevation, canopy):
-			var becomes: String = rule.get("becomes", "")
-			if becomes == "classify":
-				return BiomeClassifierScript.classify(tile)
-			return becomes
-
-	return tid
+static func ideal_terrain(tile: RefCounted, spec: Dictionary) -> String:
+	## Determine the climate-ideal terrain type for a tile.
+	var tile_dict: Dictionary = {
+		"biome_id": tile.get("biome_id"),
+		"temperature": tile.get("temperature"),
+		"moisture": tile.get("moisture"),
+		"elevation": tile.get("elevation"),
+		"canopy_cover": tile.get("canopy_cover"),
+	}
+	var spec_json: String = JSON.stringify(spec)
+	return GdClimateSpecEval.ideal_terrain(tile_dict, spec_json)
 
 
-static func eval_condition(cond: String, temp: float, moist: float, elev: float, canopy: float = 0.0) -> bool:
+static func eval_condition(
+	cond: String, temp: float, moist: float, elev: float, canopy: float = 0.0
+) -> bool:
 	## Evaluate a condition string from climate_spec.json.
-	## Supports: "field op value", "cond1 AND cond2", "cond1 OR cond2".
-	## Fields: temperature, moisture, elevation, canopy.
-	## Operators: <, <=, >, >=.
-	if " OR " in cond:
-		var parts: PackedStringArray = cond.split(" OR ")
-		for part: String in parts:
-			if eval_condition(part.strip_edges(), temp, moist, elev, canopy):
-				return true
-		return false
-
-	if " AND " in cond:
-		var parts: PackedStringArray = cond.split(" AND ")
-		for part: String in parts:
-			if not eval_condition(part.strip_edges(), temp, moist, elev, canopy):
-				return false
-		return true
-
-	var clean: String = cond.strip_edges().trim_prefix("(").trim_suffix(")")
-	var tokens: PackedStringArray = clean.split(" ")
-	if tokens.size() < 3:
-		push_warning("ClimateSpecEval: bad condition: '%s'" % cond)
-		return false
-
-	var field: String = tokens[0]
-	var op: String = tokens[1]
-	var value: float = float(tokens[2])
-
-	var actual: float = _field_value(field, temp, moist, elev, canopy)
-	if actual == -INF:
-		return false
-
-	return _check_op(actual, op, value)
+	return GdClimateSpecEval.eval_condition(cond, temp, moist, elev, canopy)
 
 
-static func ley_channeling_mult(tile: Variant, spec: Dictionary) -> float:
+static func ley_channeling_mult(tile: RefCounted, spec: Dictionary) -> float:
 	## Corruption spread multiplier based on receiving tile's ley state.
-	## Reads multiplier values from climate_spec.json ley_channeling section.
-	if tile.ley_line_count <= 0:
-		return 1.0
-
-	var ley_spec: Dictionary = spec.get("ley_channeling", {})
-	var school: String = tile.ley_school
-	if school == "death":
-		return ley_spec.get("death_ley", 3.0)
-	if school in ["nature", "life"]:
-		return ley_spec.get("nature_life_ley", 0.5)
-	return ley_spec.get("on_ley_generic", 2.0)
-
-
-static func _field_value(field: String, temp: float, moist: float, elev: float, canopy: float = 0.0) -> float:
-	match field:
-		"temperature":
-			return temp
-		"moisture":
-			return moist
-		"elevation":
-			return elev
-		"canopy":
-			return canopy
-	push_warning("ClimateSpecEval: unknown field '%s'" % field)
-	return -INF
-
-
-static func _check_op(actual: float, op: String, value: float) -> bool:
-	match op:
-		"<":
-			return actual < value
-		"<=":
-			return actual <= value
-		">":
-			return actual > value
-		">=":
-			return actual >= value
-	push_warning("ClimateSpecEval: unknown op '%s'" % op)
-	return false
+	var tile_dict: Dictionary = {
+		"ley_line_count": tile.get("ley_line_count"),
+		"ley_school": tile.get("ley_school"),
+	}
+	var spec_json: String = JSON.stringify(spec)
+	return GdClimateSpecEval.ley_channeling_mult(tile_dict, spec_json)