We all should work together to build a sustainable future

The theory of “overkill hypothesis”, that humans wiped out megafauna or giant beasts, was created by geoscientist Paul Martin over four decades ago.

He was inspired by a rise in radiocarbon dating, which plotted a direct correlation between the arrival of the first humans and the extinction of the giant mammals.

However, more recently, other archaeologists have challenged this theory. Some researchers argue that of the 36 animals that went extinct, only two - the mammoth and the mastodon - show clear signs of being hunted.

Other scientists found a direct link between when the animals died out or evacuated regions, and changes in global temperatures.

Irrespective of which of the conflicting theories is true, the World Wildlife Fund (WWF) announced last week that as many as 52%  of the world’s vertebrates - mammals, birds, reptiles, amphibians, and fish - were lost between 1970 and 2010 because humans are destroying habitats and consuming animals faster than they are able to reproduce.

The conservation group’s Living Planet Report, published every two years, said humankind’s demands were now 50% more than nature can bear, with trees being felled, groundwater pumped and carbon dioxide emitted faster than Earth can recover.

Carbon dioxide emissions, agricultural pollution, and stress on water supplies are leading to potentially irreversible changes to the environment, driven primarily by demands for energy and consumer goods in rich, industrialised nations.

WWF tracked population trends in 10,380 groups of 3,038 vertebrate species. The 52% decline is steeper than in previous WWF reports on animal populations because the organisation used a “better representation” of species. The report states there is no sign the trend will reverse.

Animals living in freshwater environments have been hit hardest - declining 76%. Marine and terrestrial populations fell 39%. The biggest declines occurred in South America and the Asia-Pacific region.

Industrial and agricultural practices that pollute the atmosphere and oceans, as well as growing demands on freshwater supplies are unsustainable, says WWF, and could trigger catastrophic changes to ecosystems and the climate.

Humans are emitting more carbon dioxide than the Earth’s trees and oceans can absorb, putting the planet on track to exceed the 3.6 degree Fahrenheit rise in average global temperatures that some scientists have identified as a threshold for avoiding dangerous changes to the climate system.

While nitrogen-enriched fertilisers have helped boost agricultural production over the past 60 years, they also pollute rivers, lakes and streams, states the report. Untreated wastewater in urban areas also disrupts aquatic ecosystems. High concentrations of nitrogen in waterways causes algae to bloom, which deprives rivers or lakes of oxygen and produces “dead zones”, where no life can survive.

Agricultural production accounts for over 90% of the world’s freshwater consumption and many countries are depleting supplies faster than they can be replenished. Areas of the US, China, and India are particularly vulnerable to water scarcity. Each is largely self-sufficient in agricultural production but prolonged drought could cut into each nation’s crop yields.

However, there is still hope if politicians and businesses take the right action to protect nature. As WWF International director general Marco Lambertini stated: “It is essential that we seize the opportunity - while we still can - to develop sustainably and create a future where people can live and prosper in harmony with nature.”