Prohibit weather modification.

- 2025
69th Legislature 2025 SB0473.2
- 1 - Authorized Print Version – SB 473
1 SENATE BILL NO. 473
2 INTRODUCED BY B. PHALEN, D. LOGE
3
4 A BILL FOR AN ACT ENTITLED: “AN ACT GENERALLY REVISING LAWS RELATED TO WEATHER
5 MODIFICATION; PROHIBITING WEATHER MODIFICATION GEOENGINEERING; PROVIDING
6 DEFINITIONS; AND PROVIDING AN EXCEPTION; AND PROVIDING AN IMMEDIATE EFFECTIVE DATE.”
7
8 BE IT ENACTED BY THE LEGISLATURE OF THE STATE OF MONTANA:
9
10 NEW SECTION. Section 1. Prohibiting weather modification BY GEOENGINEERING. (1) THE
11LEGISLATURE FINDS THAT GEOENGINEERING POSES RISKS TO THE ENVIRONMENT AND PUBLIC HEALTH DUE TO ITS
12EXPERIMENTAL NATURE AND POTENTIAL FOR UNINTENDED CONSEQUENCES.
13 (2) Except as FOR WEATHER MODIFICATION BY CLOUD SEEDING AS prescribed in 85-3-101 through 85-
14 3- 424 TITLE 85, CHAPTER 3, a person may not intentionally inject, release, or disperse chemicals, chemical
15 compounds, substances, or apparatuses within the borders of Montana expressly for: GEOENGINEERING.
16 (a) engaging in weather modification and control;
17 (b) affecting temperature; or
18 (c) affecting the intensity of the sunlight.
19 (2)(3) As used in this section:
20 (a) "chemical compounds" means any combination of any number of chemicals;
21 (b) "chemicals" means industrial substances, whether simple, compound, or obtained through the
22 process of the science and art of chemistry, whether of organic or inorganic origin; and
23 (c) "weather modification and control" means changing or controlling or attempting to change or
24 control, by artificial methods, the natural development of atmospheric cloud forms or precipitation forms that
25 occur in the troposphere.
26 (A) "CLOUD SEEDING" MEANS A PROVEN METHOD OF INCREASING PRECIPITATION WITHIN EXISTING CLOUD
27SYSTEMS TO SUPPORT WATER RESOURCE MANAGEMENT EFFORTS, INCLUDING FOR AGRICULTURE AND SNOW MAKING.
28 (B) "GEOENGINEERING" MEANS LARGE-SCALE, INTENTIONAL INTERVENTIONS IN THE EARTH'S CLIMATE
- 2025
69th Legislature 2025 SB0473.2
- 2 - Authorized Print Version – SB 473
1SYSTEM DESIGNED TO COUNTERACT OR MITIGATE GLOBAL CLIMATE CHANGE, INCLUDING STRATOSPHERIC AEROSOL
2INJECTION, SOLAR RADIATION MANAGEMENT, AND MARINE CLOUD BRIGHTENING, THAT INVOLVE ALTERING ATMOSPHERIC,
3OCEANIC, OR TERRESTRIAL SYSTEMS ON A PLANETARY SCALE WITH POTENTIALLY UNPREDICTABLE AND WIDESPREAD
4ENVIRONMENTAL CONSEQUENCES.
5 (C) "MARINE CLOUD BRIGHTENING" MEANS SPRAYING SEA SALT PARTICLES INTO MARINE CLOUDS TO
6INCREASE REFLECTIVITY AND REDUCE THE SOLAR RADIATION ABSORBED BY THE EARTH.
7 (D) "SOLAR RADIATION MANAGEMENT" MEANS MANAGING SOLAR RADIATION REACHING THE EARTH'S
8SURFACE THROUGH STRATOSPHERIC AEROSOL INJECTION, SPACE-BASED REFLECTORS, OR CLOUD ALBEDO
9ENHANCEMENT.
10 (E) "STRATOSPHERIC AEROSOL INJECTION" MEANS INJECTING REFLECTIVE PARTICLES INTO THE
11STRATOSPHERE TO REFLECT SUNLIGHT AND REDUCE GLOBAL TEMPERATURES.
12
13 NEW SECTION. Section 2. Codification instruction. [Section 1] is intended to be codified as an
14 integral part of Title 75, chapter 2, and the provisions of Title 75, chapter 2, apply to [section 1].
15
16 NEW SECTION. SECTION 3. EFFECTIVE DATE. [THIS ACT] IS EFFECTIVE ON PASSAGE AND APPROVAL.
17 - END -