So far, all of you have offered problems which can be alleviated by two words which were already posted: "Legalize it".
China rising? China now supplies roughly $500m/yr of hemp products to the United States while the US government spends at least $20b/yr to wipe out ditchweed hemp. So the US spends $20.5b each year to buy from China the exact same resource that we destroy at home. Does anyone wonder why China is surpassing us?
Greenhouse Effect? The USDA reported in 1916 (almost 100 years ago) that one acre of Cannabis hemp can provide 4 times more paper per acre than trees. Legalize Cannabis Sativa again, use hemp for paper products, and leave the trees in the ground to clean the environment. Is that really so difficult to understand?
Education system. Your government has purposefully removed any mention of Cannabis' contribution to helping America win World War II because they don't want any positive information about this resource to reach the general voting public, because that would make the drug war look like a bunch of "government overreach". Highschool 4-H clubs during WWII were given school credits for growing hemp for the war. The government urged students to grow at least a half acre each, but preferably 2 acres per student. Legalize Cannabis Sativa again, end the big government drug war that was started over lies, and use the billions of dollars that we will save each year to improve our schools and make America independent and prosperous like we were during WWII. This might also help take care of the problem of American ignorance and stupidity.
End plutocracy. The global economy is based on energy- the power to mass produce and transport goods. Electricity and transportation fuel are currently based on fossil fuels, consolidating global profits mainly to the nations and the corporations with access to those fossil fuels. Electricity and transportation fuel can both be supplied by widespread production of Cannabis Sativa, leaving fossil fuels deep underground where they can't poison the world. And because Cannabis grows tall and fast in nearly every climate, global production of hemp will help reduce the amount of CO2 in the atmosphere.
Let's give this a try again, America:
We know it works because we won World War II and lost the drug war.