Along the history,the Earth has experienced five major episodes of mass extinctionsassociated with climatic changes that have modified the characteristics of the entire planet. An article in the magazineNature, in which researchers from the Higher Council for Scientific Research (CSIC) have participated, analyzes the forces that “may be leading”a new change in planetary stateand provides possible tools to minimize its consequences.
The times of transition that the Earth has experienced throughout its history represent only 5%. The rest of the time it has been stable. The last great change took place about 14,000 years ago, when 30% of the earth’s surface lost the ice sheet that covered it during the last glacial period. The last ice age had lasted about 100,000 years, while the transition period lasted just over three millennia. Since then, the planet has maintained more or less stable characteristics until the appearance and development of human civilization.
The researcher at the Doñana Biological Station Jordi Bascompte, who has participated in the work, affirms that “humans are causing changes that could lead to a new planetary state; these changes seem to involvealterations in the chemistry of the atmosphere and oceans, and major disruptions in energy flows from the beginning to the end of the food chain. “
The research highlights that humanity, therefore, is the main promoter of the circumstances that are motivating this change in the planetary state. The increase in population is associated with greater consumption of resources and energy, and the transformation and fragmentation of the landscape that alter atmospheric, oceanic and terrestrial conditions that, in turn, threaten the survival of current biodiversity.
Humanity grows
Theannual growth rateof the population is about77 million people, almost 1,000 times higher than that experienced between 10,000 and 400 years ago, when it was around 67,000 people. The study highlights that the increase in population has brought about the transformation of 43% of the earth’s surface into urban and agricultural areas. Similarly, humans control theuse of up to 40% of world primary production, which limits the access of other species to this resource. In turn, the consumption of fossil fuels has led to an increase in the concentration of CO235% atmospheric and has caused a decrease of 0.05 in oceanic pH.
The impact of the set of alterations that the planet is suffering is greater than the individual sum of each of these alterations. Eloy Revilla, also a researcher at the Doñana Biological Station of the CSIC and collaborator of the work, considers that “if these direct impacts exceed 50%, even the undisturbed areas of the planet will suffer the consequences. According to the article, “if the population growth rate is maintained and so does the level of resource consumption, this percentage will be reached by 2025 and will reach 55% in 2045.”
Minimize impacts
What will happen when these levels of impact are reached is still uncertain, but Revilla believes that “these percentages should seriously concern us. However, some consequences are intuited, such as the loss of environmental services. The article points out aspects such as a loss of productivity in farmland, a lower CO2 storage capacity and the collapse of the fish stock.
In order tominimize these possible impacts and do not exceed the 50% impact barrier, the article proposes the following measures: reduce the annual growth rate of the population and its associated consumption of resources, replace the highest possible energy level with renewable sources, increase the efficiency in food production and improve the management of the areas of Earth that have not yet been dominated by humans. According to the article,humanity is at a critical crossroadsin which you must decide if you want to guide the changes of the planet or just let things happen.
