Much of the success of the green revolution was created by the combination of high rates of investment in crop research, fertilizer, infrastructure, economic and market development and implementing policies to support agriculture. All these things were identified as producing the long-term consequences of rising greenhouse gas pollution, as well as ozone depletion by CFCs, and nitrogen oxides contamination from fertilizer in the U.N.'s 1972 Stockholm Conference on the Human Environment, which named them as some of the primary threats to "civilization." One of the result of the “green revolution” was the formation of dead zones that form from excess nitrogen and phosphorus nutrient pollution.
Storm water runoff containing excess nutrient pollution combined with mild weather encourages the explosive growth of phytoplankton, which is a single-celled algae. While the phytoplankton produces oxygen during photosynthesis, when there is excessive growth of algae the light is chocked out and the algae die and fall to the bottom of the near shore estuaries. The phytoplankton is decomposed by bacteria, which consumes the already depleted oxygen, leaving dead fish and shell fish in their wake.
The excess nutrients that create the dead zones are washed from agricultural fields and animal feed lots as well as from waste water treatment plants and fertilized landscapes. In the 21st century some of these algae blooms became toxic. Not all algal blooms are toxic or hazardous. Only certain species of blue-green algae form the toxin, for reasons that aren't fully understood. Toxic bacteria were not a problem until the 21st century, though algae blooms have been a problem in many places for over half a century. Only algae that contains microcystine or cyanobacteria, a toxin produced by microcystis, a type of blue-green algae that spreads in the summer algae bloom are hazardous.
In the 21st century toxic or hazardous algal blooms have become a global concern in lakes, rivers and oceans. Hazardous algal blooms, the ones that contain microcystis a type of blue-green algae produce Microcystine or cyanobacteria toxins, that can lead to the poisoning of fish, shellfish, birds, livestock, domestic pets and other aquatic organisms that can lead to human health impact from eating fish or shellfish exposed to toxins as well as drinking water contaminated by toxins. We are killing the oceans. Toxic algae blooms and dead zones are just one impact on the planet from mankind.
For more than 100 years mankind has been burning ever increasing amounts of coal, oil, and natural gas to power their homes, factories, and vehicles. Burning these fossil fuels releases carbon dioxide, a heat-trapping gas, also called greenhouse gases, into the atmosphere. They exist naturally in the atmosphere, where they help keep the Earth warm enough for plants and animals to live. But people are adding extra greenhouse gases to the atmosphere which is the main reason why the climate is changing.
The anticipated impacts of climate change are arriving. Unfortunately, many scientists believe that we have passed the tipping point which a few years ago was set a 400 parts per million of CO2 in the atmosphere. We have decisively passed that CO2 level and it appears certain that atmospheric CO2 levels will continue higher. Many scientists say that once past the tipping point there will be drastic changes in earth’s climate even if we stop emitting CO2.
The IPCC (Intergovernmental Panel on Climate Change created by the World Meteorological Organization) considers some additional warming of the planet to be irreversible. According to the IPPC, “Many aspects of climate change and associated impacts will continue for centuries, even if anthropogenic emissions of greenhouse gases are stopped. The risks of abrupt or irreversible changes increase as the magnitude of the warming increases.” The expected impacts are continued warming of the planet, rainfall pattern changes and significant rising of sea level.
Surface water has throughout history served as the principal freshwater supply used by mankind. However, the importance of groundwater has increased in recent decades as mankind’s demand for water has surpassed surface water supplies and our ability to access groundwater has increased with technology. Regions of the earth have come to rely more heavily on groundwater as a dependable water supply source. Groundwater represents almost half of all drinking water worldwide, though a lesser proportion of irrigation water and is currently the primary source of freshwater for approximately two billion people [Famiglietti, 2015].
Although there is no measured basis, it is commonly accepted that groundwater comprises 30% of global freshwater. This percentage was estimated in a 1978 paper which assumed uniform groundwater supply across the entire global land area. This assumption is not likely to be accurate, but has been used to estimate groundwater supplies in critical regions. Nonetheless, groundwater is an essential portion of the water supply and ecology. For groundwater to remain available indefinitely there must be a balance between the volume of water that enters a groundwater system and the volume that leaves the system over time.
The climate of the planet has continually changed over the millennia and some groundwater aquifers are legacies of an earlier climate and are not being recharged. There are some groundwater systems that have no natural recharge; unless they are artificially recharged they have a limited life span. If the water from a groundwater basin is used faster than it is recharged, it is being used up and ultimately it will run out.
Mankind’s ecological impact on our planet is huge. The human population is currently estimated at about 7.8 billion people, but cannot continue to grow indefinitely. There are limits earth’s resources and how efficient we can be in using them. Scientists believe there is maximum number of a species an environment can support indefinitely. There is a carrying capacity for life on earth, but no agreement on what that number is. It is very difficult for ecologists to estimate what the human carrying capacity of earth is. We are a complex species and do not consume resources and interact with the environment in a uniform way. According to an article from the Australian Academy of Science, ‘An average middle-class American consumes 3.3 times the subsistence level of food and almost 250 times the subsistence level of clean water.” Thus, “if everyone on Earth lived like a middle class American, then the planet might have a carrying capacity of around 2 billion.” The lower the quality of life to subsistence consumption the more people earth can support.
In April 1973, a dystopian film called Soylent Green was released. In this film the omniscient Soylent Corporation is responsible for nearly all food production. Everyone eats wafers made from plankton called Soylent Green. In the course of investigating a death the protagonist a police officer discovers in the climactic scene that Soylent Green is being made from people. “Solent Green is people! The ocean's dying, the plankton's dying. It's people. Soylent green is made out of people.” The movie took place in the year 2022 in New York. I do not expect that dystopian vision of the future to occur, but I do expect that in a century or two the human population on earth will be smaller than it is now.