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Table of Contents
What is Climate Change?
Climate change is affecting our planet in many different ways, including global warming. The rate at which the Earth’s temperature has increased over the past 100 years has risen rapidly. This is mostly due to the release of greenhouse gases from the burning of fossil fuels. Volcanic eruptions, wildfires and the burning of fossil fuels, like oil, coal, and natural gas, release gases. These gases, called greenhouse gases, include carbon dioxide, chlorofluorocarbons, water vapor, methane, and nitrous oxide.
As their name suggests, greenhouse gases create a greenhouse effect. When the sun’s rays enter our atmosphere, they warm up the Earth. Heat that is reflected off the Earth’s surface cannot escape, but is trapped by greenhouse gases, making it warmer. This is crucial to the survival of the Earth’s living organisms, keeping the atmosphere at an inhabitable temperature. Too much warming, however, is what is currently concerning people across the globe.
Some of today’s animal species have been around for millions of years. Some insects, such as dragonflies, were on the planet 300 million years ago, before the age of dinosaurs. Other animals, like bison, bears, deer, and many others, survived the last ice age and thrive today.
The Earth has gone through natural cycles of warm and cold periods before. There have been five ice ages during the Earth’s 4.5-billion-year history. During these times, much of the Earth was covered in vast ice sheets. Conversely, there have also been several hot periods. Today, the global average temperature is just shy of 60oF (15.5oC), whereas 55 million years ago it was more like 73oF (22.7oC). The concern today is that the warming of the Earth is happening faster than it has before. This doesn’t allow plants and animals enough time to adapt to the change.
How does climate change affect plants?
Scientists predict global temperatures to increase by 2.7–3.6oF (1.5–2oC) by 2050. They also estimate the human population to reach 9 billion by the same year. This means that we need to grow more food to feed more than an additional billion people from this year. But climate change is making this challenging. We are already seeing significant weather extremes. Over the last few decades, we have seen an increased frequency of heat waves, less rainfall and more droughts, excessive flooding, and intense weather storms. These conditions are affecting crop growth.
Although higher levels of carbon dioxide can initially boost crop growth, there are negative effects. Plants use carbon dioxide to grow, but having too much in the air causes global warming, which negatively affects plants. Environmental temperatures just a few degrees above the norm can inflict significant losses in crop yield. Flooding threatens harvests around the world and increases the likelihood of plant diseases. Crop quality and crop growth are also both negatively impacted by heat stress.
Short-lived plants seem to be adapting to climate change, however. This includes some crops that we grow for food. Some plants, like weedy field mustard, have survived increases in dry weather. They have been shown to flower earlier in the year in order to take advantage of wetter conditions before a prolonged dry spell.
Unlike animals, plants can alter their physical appearance when environmental conditions change. In cold weather, thale cress is a plant that looks compact. Its leaves are bunched and low to the ground. However, when the plant grows in a warmer climate, the leaves stick out more and grow up off the ground. The plant is less compact. This form reduces the intensity of radiation from the sun and allows circulation of air around each leaf, dissipating the heat.
Many cultivated crops lost their ability to adapt to climatic conditions during domestication. People bred the crops for other traits, such as faster growth, bigger size, or a particular color or flavor. Scientists are now trying to breed or engineer crops to tolerate harsh weather conditions.
How does climate change affect animals?
As everything in ecology is connected, a change to one species can cause a cascading effect. Songbirds have been observed in this way. Warmer temperatures cause plants to sprout new leaves earlier in the year. Consequently, insect populations that feed on new leaves erupt and thrive earlier. Songbirds that feed on these insects can feed their chicks well. So, in subsequent years, the birds breed earlier to take advantage of the abundant food source. In 50 years, some bird species have brought forward their breeding season by 2 weeks. This is a significant amount of time in these birds’ lifecycles.
Mandt’s black guillemots, a seabird, are also shifting the timing of their breeding. They rely on sea ice for resting and catching fish. As the sea ice is melting earlier each year, these birds have shifted their breeding season earlier too. Unfortunately, their populations are shrinking, as they rely so heavily on the sea ice.
Fairy wrens usually breed during the Australian wet season. However, because dry seasons are becoming drier, the hatchlings may struggle during times of drought. The birds have adapted their breeding timing to harsher dry seasons, now commonly breeding during dry weather. This means that the chicks hatch at the end of the dry season, in time for plentiful food and water.
Warming global temperatures are melting the polar ice caps. This is alarming, for two reasons. Firstly, the melted ice is causing sea levels to rise. This will cause flooding and a significant loss of coastal areas around the world. Secondly, polar bears rely heavily on ice to hunt their favorite prey, ringed seals. Polar bears are ambush predators. They hunt these seals by waiting patiently at seal breathing holes in the ice. When a seal pops its head up through a breathing hole, the polar bear can pounce on it. Without ice, polar bears find it very difficult to hunt.
A small population of polar bears, however, are adapting to this change in sea ice. They have found a way to continue to hunt ringed seal: they have moved onto glacial ice. This is freshwater ice that has broken off from glaciers and floats on the sea. For about 250 days of the year, when the sea ice has all melted, the polar bears can use the freshwater ice to hunt. This behavioral adaptation has enabled the polar bears to survive where they may have otherwise starved.
White sifaka lemurs live on Madagascar. They are one of the world’s most endangered animals. They have silky white and golden fur with black faces, and spend most of their time in trees. When they do venture to the ground, they walk on their back legs using their arms for balance. These lemurs have fewer sweat glands than other primates, so they can overheat easily. With increases in temperatures, they have adapted their behavior to help keep them cool on exceptionally hot days. They have been observed hugging trees. They stand on the ground and wrap their arms around tree trunks. The trees are about 9oF (5oC) cooler than the surrounding environment. Hugging the tree trunks helps the lemurs stay cool.
Although the Earth has been through many cycles of warm and cold periods in history, the rate at which global warming is happening today is alarming. Environmental pressures have caused species to go extinct before. Those that didn’t adapt, died out. But many did find solutions to a change in climate. These adaptations could include a change in behavior, such as migrating to warmer or cooler areas, or a change in physical traits, such as thicker fur or smaller body size. If the change in climate happens too quickly, however, it does not give species enough time to adapt and survive. This is the concern today. Therefore, we need to tackle climate change. All of Earth’s species are connected throughout the delicate balance within our ecosystems.
fossil fuels: fuels created by dead plants and animals millions of years ago. When we burn them carbon dioxide is released in huge amounts
heat waves: when the daily maximum temperature is hotter than average by at least 9oF or more over at least 5 consecutive days
crop yield: the volume of crops grown in a season
ecology: the study of the relationships between organisms and their surrounding environment
polar ice caps: frozen bodies of ice found at the North and South Poles
glaciers: frozen rivers
extinct: when a species no longer has any living members
Flesch Kincaid Grade Level: 7.1
Flesch Kincaid Reading Ease: 67
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https://www.climate.gov/news-features/climate-qa/whats-hottest-earths-ever-been#:~:text=One%20of%20the%20warmest%20times%20was%20during%20the,between%20500%20million%20and%20250%20million%20years%20ago. Accessed on 21 October 2022
Wong, C. (2022) New Scientist. Polar bears adapting to climate change by hunting on freshwater ice.
Study.com (2022) Sifaka Lemurs: Facts, Locomotion & Habitat
https://study.com/academy/lesson/sifaka-lemurs-facts-locomotion-habitat.html Accessed on 23 October 2022
Kemeny, R. (2022) New Scientist Lemurs hug tree trunks to cool down when temperatures top 30°C
https://zephr.newscientist.com/article/2339165-lemurs-hug-tree-trunks-to-cool-down-when-temperatures-top-30c/#:~:text=Lemurs%20seem%20to%20hug%20trees%20to%20keep%20cool,base%20of%20tree%20trunks%20on%20particularly%20hot%20days. Accessed on 23 October 2022
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