There are many arguments surrounding whether or not marijuana should be grown and used for medical reasons.

But the impact on the climate is one factor in the debate that may have been overlooked - until now.

A new report, by a clean energy policy research institute, has found growing marijuana makes up one per cent of energy use in states such as Colorado and Washington.

The impact on the climate is one factor in the debate that may have been overlooked, until now. A new report, by a clean energy policy research institute, has found growing marijuana makes up 1 per cent of energy use in states such as Colorado and Washington. Stock image

LEGALISING AROUND THE WORLD In November nine US states, including California, will vote on marijuana legalization. But the move towards legalizing is not just happening in the US. In February this year, former UN Secretary-General Kofi Annan said 'we need to accept that a drug-free world is an illusion,' adding it was time to legalize and regulate personal drug use. Medicinal marijuana will be legalized across Australia from November this year, under a formal decision reached by the Therapeutic Goods Administration last month. Cannabis should be legalised for 'medicinal' use in the UK, a major report concluded last month. Advertisement

It says the energy needed to run cannabis farms may soon rival the expenditures from big data centers.

These are estimated 100 million metric tons of carbon into the atmosphere every year, according to Takepart.com.

The report also warns banks are reluctant to do business with cannabis farms to give them finance to invest in energy efficiency and renewables, even in areas where growing it is legal.

'Utilities and local and state regulators have yet to consider the energy impacts of marijuana cultivation comprehensively,' said Kelly Crandall, an analyst for EQ Research, who wrote the report.

EQ Research is a clean energy policy research institute based in North Carolina.

Growing marijuana can use a lot of energy because the operations need to be dehumidified, air-conditions and illuminated.

'Marijuana cultivation may be viewed as a burden that will lead to higher costs and larger environmental footprints.'

The report found a large marijuana-growing operation can use as much as 21,500 watts per square feet (2,000 watts per square meter) because of the constant need for lighting and ventilation.

'Anecdotally, marijuana businesses can spend anywhere from a few thousand dollars to $100,000 (£78,628) per month in energy costs,' the report said.

'On top of which they often must make significant investments to pay for utility upgrades to provide them with electric services.'

In November nine US states, including California, will vote on marijuana legalisation. Because marijuana cultivation is still a criminal offence under federal law, most banks will not do business with the industry even in states where it is legal (shown)

To make things worse, high interest rates, regulation on other aspects of the business and disconnects between business owners and the growers they employ can prevent investments in energy efficient equipment or renewable energy.

'Because marijuana cultivation remains federally illegal,' the report said, 'removing barriers will require collaboration between various entities within states.'

For example, because marijuana cultivation is still a criminal offence under federal law, most banks will not do business with the industry even in states where it is legal.

Growing marijuana can use a lot of energy because the operations need to be dehumidified, air-conditions and illuminated. Ms Crandall said one option was for farmers to take their plants outside, which could cut down on many of the heating and lighting costs. Stock image

HOW CANNABIS CAN DAMAGE CRITICAL BRAIN CIRCUITS A world-first study published last month identified how cannabis can damage brain circuits to cause significant long-term damage. As our brains develop, we form neural circuits which hold our short-term memory. This process pushes out unnecessary projections, leaving only correct systematic connections in the circuit. These circuits allow us to retrieve recent information such as where you left your keys or what someone just said. They also act as a foundation for long-term memory. New research reveals marijuana unnecessarily trims the connections that form these circuits, leading to gaps. The findings by Japan's Osaka University offer a small but significant insight into how cannabis could affect the brain long-term amid a rapid swing in favour towards legalization in the United States. It could also help researchers exploring dementia and brain damage. The most striking result of the research was its detailed map of a brain pathway that has, until now, remained elusive. Advertisement

'I find it kind of a conundrum that it's a very cash-rich industry, but because of banking restrictions it also has a difficulty investing in solar and efficiency,' Ms Crandall told Take Part.

Ms Crandall said one option was for farmers to take their plants outside, which could cut down on many of the heating and lighting costs.

The report, named 'A Chronic Problem: Taming Energy Costs and Impacts from Marijuana Cultivation', pulled from utility filings, interviews, and other published information, although primary information and current research into grow centres' energy costs was hard to find, Ms Crandall said.

'It's pretty difficult to get people to comment on the record.'

The carbon cost of cannabis around the world is likely to grow in the next few years.

In November nine states, including California, will vote on marijuana legalization. But the move towards legalizing is not just happening in the US.

In February this year, former UN Secretary-General Kofi Annan said 'we need to accept that a drug-free world is an illusion,' adding it was time to legalize and regulate personal drug use.

Medicinal marijuana will be legalized across Australia from November this year, under a formal decision reached by the Therapeutic Goods Administration last month.