Deforestation and Erosion


Many people illegally growing marijuana place their grow sites in forests, particularly in California. These areas, often public lands, are difficult to reach and hard for law enforcement to monitor, making them good for concealing the growers’ activities. But to plant crops in these remote, often hilly or mountainous, locations, growers must first clear away trees to create enough open land. They also often clear away the under-growth, both of which contribute to increased soil erosion because there are fewer plants holding soil in place. Ultimately, this also increases the risk of landslides.

Individual growing areas can be up to several acres or even square miles and can be spread over multiple sites. In northern California alone, the amount of land used for illegally growing marijuana has doubled in the last five years. This illegal land use is contributing to deforestation and eliminating animal habitats, which are discussed further in other posts.

Illicit Water Use

California Drought Water School

Marijuana is a water-intensive crop to grow, using approximately six gallons of water per plant per day. Grow sites often illegally divert water from rivers and streams, and lay miles of illegal irrigation tubes. At just one illegal grow in northern California, law enforcement officials found a set of seven sites with a total of eight and a half miles of irrigation piping.

The water needs of these sites are high enough to totally deplete some streams and rivers, harming fish and wildlife in the areas, as well as official efforts to revitalize their populations. Made worse by California’s severe drought, there are cases of streams literally being sucked dry by marijuana farms, and the state has several large rivers at historically low water levels. In addition to using a lot of water, marijuana growers also often pollute water. The insecticides, fertilizers, and other chemicals they use not only seep into soil and ground water, but can also enter streams and rivers, harming the fish and wildlife that rely on them.

Dangers of Pesticide Use


More than one recent scientific study has found that chemicals used in the illegal cultivation of marijuana are having harmful consequences on animals in the surrounding areas (see links to these studies below). Many people growing marijuana use pesticides to protect their crops from harmful insects and other pests, as well as fertilizers and other chemicals, thereby increasing their crop yields. These harsh chemicals, however, are not only hazardous to insects but to humans and the environment as well. In addition, these growers are not only using these chemicals without proper authorization, they often use chemicals that are not approved for use in the United States.

Many of these pesticides and fertilizers can leak into soil and water supplies, and many pesticides leave traces of chemicals in plant products. In the case of marijuana, people can breathe in as much as 70 percent of these remaining chemicals when smoking plants grown with pesticides. Using these chemicals can also create toxic runoff (runoff is the flow of water over land, usually because the soil cannot absorb it quickly enough). These streams carry the polluted water to other areas, killing off insect life in those places in addition to those near the marijuana crops and throwing off ecosystems. Other animals (and people) using these streams and rivers for water are also harmed by the chemicals that end up in them.

Another issue to keep in mind is that toxins pass up a food chain. Most of the forest animals whose deaths scientists have connected to marijuana grows were not poisoned directly, rather they were affected by eating animals that had been. These toxins pass on to each animal that consumes another that has been exposed. This has the potential to eventually cause these chemicals to enter the human population, most likely via hunters eating whatever game they have killed.

For further reading:


Endangering Animals


Marijuana production can have several adverse effects on animal habitats and populations. Illegal growers often use pesticides, insecticides, and rodenticides, which can kill more than just the intended targets. Rodenticides have been especially harmful, particularly in national forests in California, where the Pacific fisher has become a threatened species in part due to a drop in its population linked to incidents of the animals eating other animals who have been poisoned by rodenticides.

These chemicals kill not only the intended species but also other animals that consume the poisoned animals or the poisons themselves. Besides the Pacific fisher, the illegally used chemicals are killing off rodents native to the forests, as well as larger animals; a game warden found a black bear and her cubs convulsing after having apparently consumed pesticides. Evidence of them has been found in many other species, including spotted owls and foxes. Because carnivores subsist by eating other species, they will eat animals that have suffered chemical poisoning, passing the poison up the food chain, with each subsequent predator; it is even possible that these chemicals could make their ways into humans this way.

Fish are also being noticeably negatively impacted by illegal marijuana production. As noted in the post on illicit water use, marijuana is a very water-intensive plant to grow and growers often illegally divert water for their crops. This can use enough water to actually cause streams to run dry and many of California’s rivers are running at very low levels, made worse by the fact that the state is in the midst of a severe drought. These dry conditions are endangering fish species that live and breed in the state’s streams and rivers, as well as undermining its projects to revitalize certain fish species. Many other animals depend on these water sources, so they are also threatened by this high water use.

Dr. Mourad Gabriel has done a lot of research on the repercussions marijuana grows have on wildlife populations; visit his organization’s website to learn more.

For more detailed reading:


High Energy Use

Screen Shot 2015-07-21 at 12.34.36 PM

Growing marijuana indoors requires very large energy inputs. A 2012 study estimated that marijuana growth in the United States accounts for one percent of the country’s energy use; that’s $6,000,000,000 worth of energy! In states with particularly high production, marijuana energy use is even higher; California’s is estimated to be three percent of the state’s total energy use. Producing one kilogram of final product indoors generates 4600 kilograms of CO2 emissions, the equivalent of 3,000,000 cars. Most of this energy goes to the lights necessary to stimulate the plants’ photosynthesis. But it is also needed for climate controls (heating and cooling, depending on the season) and dehumidification, among other uses. This problem is compounded by the fact that because growing inside provides more stable conditions, marijuana farmers are able to increase the number of harvest per year, further increasing overall energy use per year.

The photo above, and more illustrated statistics on marijuana’s water and energy use, can be seen in this Mother Jone’s piece.