Category Weather, Climate, Ecology

What is a real life example of extinction?

We are in the middle of a mass extinction brought about by human activity.

What is mass extinction?                       

A vast number of species going extinct at one period in time is called mass extinction. It is also known as a biotic crisis, as it leads to a decline in the world’s biodiversity. In a mass extinction, species disappear faster than they are replaced by new species.

What are the causes of mass extinction?

Earlier extinctions took place due to natural causes like global climate change, fluctuating sea levels and catastrophic events like volcanic eruptions or asteroid impacts. However, the ongoing extinction is the result of human actions.

How many mass extinction events have occurred on the Earth?

The Ordovician-Silurian extinction, 444 million year ago; the Devonian extinction, 360 million years ago; the  Permian extinction, 250 million years ago; the Triassic-Jurassic extinction, 201 million years ago; and the Cretaceous extinction, 65 million years ago. The first eliminated marine invertebrates, the second, tropical marine species. The third and the largest decimated most of the marine species and many terrestrial vertebrates, and the fourth destroyed all the Triassic reptiles. The fifth last was most likely caused by an asteroid hitting the Earth. It killed off dinosaurs of all species, including the remaining non-avian dinosaurs.

Are we facing a sixth mass extinction?

At present, we are in the middle of the sixth mass extinction, the Holocene extinction, which is entirely caused by the humans. It started 10,000 years ago with the beginning of agriculture and industrialization. Human activities like deforestation, climate change, and pollution have been major contributors.

These events wipe out numerous species, reshaping ecosystems and allowing the evolution of new species. They can disrupt habitats, biodiversity, ecological stru and food chains.

What is the impact of mass extinctions?

These events wipe out numerous species, reshaping ecosystems and allowing the evolution of new species. They can disrupt habitats, biodiversity, ecological structure and food chains.

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When boreal forests burn?

A large portion of our planet’s land surface is covered by forests (of different types). These include tropical, subtropical temperate, and boreal forests. While forests the world over are threatened by global warming boreal forests grapple additionally with an issue unique to them. What is it? Come; let’s find out the boreal forests of the northern hemisphere span Scandinavia, Siberia, Alaska, and Canada. Due to this vastness and the sheer number of trees they hold, these forests are an important carbon sink. Carbon has also accumulated over thousands of years in the soil due to the (long) time it takes for dead organic matter to decompose, thanks to the region’s cold climate and water-logged ground. The ecosystems here have been shaped mainly by “wildfires ignited by lightning” During these fires, due to the quantum of carbon it holds, a boreal forest “will release 10 to 20 times more carbon compared to a similarly sized fire in other ecosystems”. But then, unlike most other types of forests, these forests “might burn only once a century, sometimes even less often than that”. Because of this frequency, the amount of carbon stored has always exceeded that of carbon released into the atmosphere; it has been so for at least 6,000 years now. But now global warming is threatening this delicate balance.

Due to rising global temperatures, the fire season has become longer, leading to an increase in the frequency and severity of wildfires. As the “interval between fires shortens, more carbon is being released from organic soils in boreal forests than the ecosystems can reabsorb”. A new study shows a dramatic spike “in emissions from boreal fires over the past two decades”. In 2021 alone, they showed “a record 23% of global vegetation wildfire emissions, more than twice their contribution in a more typical year. If such spikes continue, it is likely that boreal forests may soon become a significant source of global emissions from biomass burning.

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In a tearing hurry?

Climate change is making hurricanes wetter, windier and altogether more intense. There is also evidence that it is causing storms to travel more slowly, meaning they can dump more water in one place.

If it were not for the oceans, the planet would be much hotter due to climate change. But in the last 40 years, the ocean has absorbed about 90% of the warming caused by heat-trapping greenhouse gas emissions. Much of this ocean heat is contained near the water’s surface. This additional heat can fuel a storm’s intensity and power stronger winds.

Climate change can also boost the amount of rainfall delivered by a storm. Because a warmer atmosphere can also hold more moisture, water vapour builds up until clouds break, sending down heavy rain. During the 2020 Atlantic hurricane season-one of the most active on record – climate change boosted hourly rainfall rates in hurricane-force storms by 8%-11%, according to an April 2022 study in the journal Nature Communications.

The world has already warmed 1.1 degrees Celsius above the pre-industrial average. Scientists at the U.S. National Oceanic and Atmospheric Administration This image obtained from the National Oceanic and Atmospheric Administration (NOAA), shows Hurricane Idalia making landfall in Florida on August 30, 2023. AFP (NOAA) expect that, at 2 degrees Celsius of warming, hurricane wind speeds could increase by up to 10%. NOAA also projects the proportion of hurricanes that reach the most intense levels Category 4 or 5- could rise by about 10% this century. To date, less than a fifth of storms have reached this intensity since 1851.

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How can I invest in our planet?

Earth Day, celebrated each year on April 22, just went by. With “Invest in Our Planet” as the theme, the focus is on engaging governments, institutions, businesses, and people across the world to do their part. And, this includes dedicating time, resources, and energy to solving the climate crisis. What role can we play in this? Here’s what!

Population, a concern

While there are many factors impacting the condition of our planet, one significant aspect is our population. According to the recent UN world population dashboard, India has surpassed China to become the world’s most populous nation with 142.86 crore people as against China’s 142.57 crore. When a country’s population increases, one of its most important benefits is the potential for economic growth. But a spike in population also has negative environmental implications. When the number of people in a country increases, it becomes more difficult to reduce carbon and methane emissions. Not just that, more number of people means more space required for living and more mouths to feed. This could translate to forests being cut down-for meeting both housing and farming needs. When forests go, habitats do too, and along with them the flora and fauna of the region. Apart from food and housing, people’s necessities, comforts, and luxuries also use up natural resources – more the number, faster the depletion of resources. A growing population also leads to a higher amount of pollution – in air, water, and land. This pollution affects not just humans but also animals and plants. In a world already grappling with climate change, population increase too adversely affects our environment.

What can we do?

Individual efforts can be as fruitful as collective ones. There’s so much we can do alone and as a community to be invested in the planet we call home. Here’s a glimpse into a few ways in which we can be kinder to the Earth

• Plant native saplings in your neighbourhood

• Make conscious efforts to reduce the use of plastic

• Take a pledge to choose a sustainable lifestyle

• Plan regular awareness campaigns on local environmental issues

• Conduct river and beach clean-up programmes

• Invite environmentalists and conservationists for talks

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WHAT BRINGS ABOUT THE END OF AN ICE AGE?

The rotation and revolution of Earth, the amount of solar radiation and the amount of carbon dioxide in the atmosphere are all factors that contribute to a warming up of Earth, which ends an ice age. Changes in ocean currents also have a major effect on temperatures on Earth.

Over thousands of years, the amount of sunshine reaching Earth changes by quite a lot, particularly in the northern latitudes, the area near and around the North Pole. When less sunlight reaches the northern latitudes, temperatures drop and more water freezes into ice, starting an ice age. When more sunlight reaches the northern latitudes, temperatures rise, ice sheets melt, and the ice age ends.

Credit: American Museum of Natural History

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WHAT ARE THE LARGEST BODIES OF ICE IN THE WORLD?

In today’s world, the ice sheets of Antarctica and Greenland. An ice sheet is a continuous mass of ice covering more than 50,000 km2. The ice sheet in Antarctica covers 14 million km2. It is 1.6 to 6.4 km thick and holds 30 million km2 of ice. The Greenland ice sheet covers about 1.7 million km2.

The Antarctic ice sheet is the largest block of ice on Earth. It covers more than 14 million square kilometers (5.4 million square miles) and contains about 30 million cubic kilometers (7.2 million cubic miles) of water.

The Antarctic ice sheet is about 2 kilometers (1.2 miles) thick. If it melted, sea level would rise by about 60 meters (200 feet).

The Greenland ice sheet is much smaller than the Antarctic Ice sheet, only about 1.7 million square kilometers (656,000 square miles). It is still the second-largest body of ice on the planet.

The Greenland ice sheet interacts much more dynamically with the ocean than the Antarctic ice sheet. The annual snow accumulation rate is more than double that of Antarctica. Glacial melt happens across about half of the Greenland ice sheet, whereas it is much more isolated on the far western part of Antarctica. Greenland’s ice shelves break up much faster than those surrounding Antarctica.

Both the Antarctic and Greenland ice sheets have caused the land under them to sink. Eastern Antarctica is about 2.5 kilometers (1.6 miles) below sea level because of the colossal weight of the ice sheet above it.

Credit: National Geographic

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