The majority of ecologists around the world believe that we are in the midst of the sixth mass extinction. Humanity’s impact on nature, they say, is now comparable to the five previous catastrophic events over the past 600 million years, during which up to 95 percent of the planet’s species disappeared. Here is a brief description of each mass extinction:
- The Ordovician Extinction: This extinction occurred in two phases, destroying 60 to 70 percent of all species. The cause was most likely continental shift triggering global cooling, devastating the oceans which were home to all life at the time;
- The Devonian Extinction: It was a prolonged event, with as many as seven different waves of extinction occurring by the end of the Devonian period. The causes were most likely varied, but in total the events wiped out 70 percent of all life on the planet;
- The Permian Extinction: This was the most severe in Earth’s history, with 96 percent of sea creatures and 90 to 96 percent of land creatures becoming extinct. It may have been caused by a combination of environmental collapse and a catastrophic event;
- The Triassic Extinction: It remains a mystery to paleontologists, but over the course of 10,000 years, 70 to 75 percent of all life on Earth vanished; and
- The Cretaceous Extinction: It is the most famous, as it heralded the end of the dinosaurs. At least 75 percent of all species on Earth became extinct, most likely from a series of massive asteroid impacts and the resultant climate change.
It is widely recognized around the world that climate change is the main cause of extinction of species. As human activities including the introduction of unnatural chemicals that contaminate the air, soil, and seas which interferes with the metabolism of animals and they are unable to cope.
In addition to climate change, here are some other causes for extinction of species:
- Overhunting: The ivory of elephants, the fur and organs of tigers, the deliciousness of tuna and the supposedly medicinal effect of shark’s fin are some examples of why these animals were over hunted to the point of extinction;
- Deforestation: It is currently the biggest cause of current extinctions. Deforestation has killed off more species than anybody can imagine. It is a fact that whole ecosystems live in the forests. It is predicted that all the rainforest can disappear in the next 100 years if nothing is done to stop deforestation. To date, 13 million hectares of forest have been converted or destroyed – nobody knows how many species have been perished. Coral reefs are also threatened. Reefs are home to 25 percent of marine animals. To date, 27 percent of coral reefs have been destroyed; and
- Overpopulation and Overconsumption: Scientists analyzed both common and rare species and found billions of regional or local populations have been lost. They blame human overpopulation and overconsumption for the crisis and warn that it threatens the survival of human civilization, with just a short window of time in which to act.
The study, published in the peer-reviewed journal Proceedings of the National Academy of Sciences, eschews calls the massive loss of wildlife a “biological annihilation” that represents a “Frightening assault on the foundations of human civilization”.
The scientists found that a third of the thousands of species losing populations are not currently considered endangered and that up to 50 percent of all individual animals have been lost in recent decades. Detailed data is available for land mammals, and almost half of these have lost 80 percent of their range in the last century. The scientists found billions of populations of mammals, birds, reptiles and amphibians have been lost all over the planet, leading them to say a sixth mass extinction has already progressed further than was thought.
Another study, recently, published in Science by researchers at seven institutions, describing a grim picture:
- A steady decline of nearly three billion North American birds since 1970, in less than a single lifetime, which represents one in four birds, primarily as a result of human activities. Climate change will further exacerbate the challenges birds are already facing from human activity.
The losses of birds include iconic songsters such as Eastern and Western Meadowlarks (Down by 139 million) and favorite birds at feeders, such as Dark-eyed Juncos (Down by 168 million) and sweet-singing White-throated Sparrows (Down by 93 million). The disappearance of even common species indicates a general shift in the ecosystems’ ability to support basic birdlife, the scientists concluded.
Here are the images of birds which are disappearing:
The news for Canada is frightening but true. All 16 Artic species would be at high risk, including iconic birds such as the snowy owl and the Arctic tern. So would nearly all – 98 percent – of the species that perch in the boreal forest, which stretches across the northern reaches of almost every Canadian province. They would include everything from tiny songbirds to big raptors.
There is always a possibility that some birds would be able to adapt by following their preferred habitat north as the continent warms. For instance, crows and magpies are already appearing in northern latitudes where before they were rarely seen.
Here are some realities:
The American Association for the Advancement of Science (AAAS) recognized the interest in understanding how species might respond to the changing climate, but predictions have varied greatly. Urban looked at over 130 studies to identify the level of risk that climate change poses to species and the specific traits and characteristics that contribute to risk. Current predictions of extinction risks from climate change vary widely depending on the specific assumptions and geographic and taxonomic focus of each study. Published studies were synthesized in order to estimate a global mean extinction rate and determine which factors contribute the greatest uncertainty to climate change–induced extinction risks. Results suggest that:
- Extinction risks were highest in South America, Australia, and New Zealand, and risks did not vary by taxonomic group;
- Realistic assumptions about extinction debt and dispersal capacity substantially increased extinction risks;
- There is an urgent need to adopt strategies that limit further climate change if in order to avoid an acceleration of global extinctions; and
- Understanding these patterns will help prepare for, and hopefully prevent, climate-related loss of biodiversity.
These concerns were published in an article, Accelerating Extinction Risk from Climate Change by AAAS in 2015, warning that:
- If climate changes proceed as expected, one in six species could face extinction.
Unfortunately, the climate conditions were deteriorated profoundly since 2015. For instance, NDP Global Outlook Report – The Heat Is On, published by the United Nations Development Programme on 18 September 2019, acknowledged the fact that the Paris Agreement will face its major test in 2020 against the backdrop of a worrying growth in greenhouse gases (GHG) emissions since the adaptation of the landmark agreement in 2015. Climate action plans known as “Nationally Determined Contributions (NDCs) are the backbone of the Paris Agreement. While this report exemplifies an optimistic view of the efforts being made by the countries around the world to fulfill their commitments, the reality associated with the current trends of climate change cannot be disregarded:
- Temperatures are already up about 1.00C from pre-industrial times and the last four years were the warmest on record – including July 2019, which was the hottest month of all;
- There are ever starker signs of harm caused by climate change; and
- Artic sea ice is shrinking, and sea levels are rising, while droughts, floods, and hurricanes grow more severe.
Here is another bad news:
Geneva, 26 November 2019 – On the eve of a year in which nations are due to strengthen their Paris climate pledges, a new UN Environment Programme (UNEP) report warns that unless global GHG emissions fall by 7.6 percent each year between 2020 and 2030, the world will miss the opportunity to get on track towards the 1.5°C temperature goal of the Paris Agreement.
Needless to say that these devastating climate conditions have and will continue to have an impact on an ecosystem, when an ecosystem is affected by climate change, it can result in the extinction of species. Those changes can inflict heavy damage on a species and their ecological niche. It must be kept in mind that there are many factors that can lead to the extinction of a species. Notably, a species’ survival is tightly linked with the ecosystem that it belongs to. The basic understanding is that when a group of organisms or a species ceases to exist, it called “Extinction”. However, a species is considered to be extinct only when the last individual of that species dies. The real challenge is to track all of the members of a single species, therefore, the exact moment of extinction is usually declared in hindsight.
Finally, Guy McPherson, a professor of Emeritus of Natural Resources and the Environment at the University of Arizona, an author of Going Dark, and one of the world’s most outspoken Climate-Change Cassandra – predicted the near-term extinction of many species, including human beings, by the middle of 2026. McPherson criticized scientists, who knew about this problem, for not doing nearly enough to educate the public. He also blamed politicians and the leaders of corporations and nongovernmental organizations for not raising the alarm.
27 November 2019 Ottawa, Ontario, Canada