Climate Change
The certainty of climate change remains a public controversy despite the consensus among approximately 97% of active climate researchers, who not only…
Global climate change is a fervently discussed topic in the news, and scientists agree that the Earth's climate is changing. But before going into what causes climate change and how scientists study it, let's clarify a few terms. The word climate is often used interchangeably with weather, but there is a difference.
Weather describes the atmospheric conditions, such as temperature, in a region over a short period of time, like a day. Climate, however, records the same conditions for the same region but over an extended period, average annual temperature for example. Global climate refers to the same variable analyzed and compiled across the entire planet. If you look at the data for average global temperature since 1880, you will see that it has been on the rise, and this is what people refer to as global warming.
One major contributor to global warming is the greenhouse effect caused by greenhouse gases, such as carbon dioxide, water vapor, ozone, and methane. These gases got their collective name because they form a layer around the Earth that is similar to the glass shield of a greenhouse. Just like the greenhouse, this layer of gas allows the Sun's rays to penetrate and then traps them, letting only a portion of the reflected rays escape back into the atmosphere and leading to a rise in temperature near the Earth's surface. Some cover of greenhouse gases is essential to ensure that the Earth's temperature stays habitable, but human activity, such as fossil fuel burning, have led to the concentration of some of these gases like CO2, which has risen above optimal levels, fueling global warming.
One major impact of this climate warming is the melting of glacial ice, which in turn results in sea level rise. This melting is exacerbated due to a phenomenon called the albedo effect. Albedo, derived from the Latin word, “albus”, meaning “white”, refers to the ratio of proportion of reflected to total solar radiation. This value will be close to one for fresh, white snow because it reflects most of the radiation. Bare soil, in contrast, has an albedo of only around 0.2, and open ocean only 0.1, and so these reflect significantly less - and so, as the climate warms, the snow melts, resulting in lower albedo, meaning that the Earth reflects less and retains more of the radiation as heat. This, in turn, causes the snow to melt more, creating a positive feedback loop and rising sea levels.
Another impact of climate change can be seen in species distribution. Species are found across a geographical area known as their range. As the climate warms, the resulting environmental changes, like melting ice caps, can cause a shift or decline in the habitable range of some of the species. Scientists have been studying these range shifts for different organisms in response to a variety of environmental variables. Using these data, they can model future changes in climate patterns and predict the likely fate of a species.
In this lab, you will assess greenhouse effects on an artificial microclimate, compare melting ice in different conditions, and study historical species' range shifts following environmental change.
Global climate change is a fervently discussed topic in the news, and scientists agree that the Earth's climate is changing. But before going into what causes climate change and how scientists study it, let's clarify a few terms. The word climate is often used interchangeably with weather, but there is a difference.
Weather describes the atmospheric conditions, such as temperature, in a region over a short period of time, like a day. Climate, however, records the same conditions for the same region but over an extended period, average annual temperature for example. Global climate refers to the same variable analyzed and compiled across the entire planet. If you look at the data for average global temperature since 1880, you will see that it has been on the rise, and this is what people refer to as global warming.
One major contributor to global warming is the greenhouse effect caused by greenhouse gases, such as carbon dioxide, water vapor, ozone, and methane. These gases got their collective name because they form a layer around the Earth that is similar to the glass shield of a greenhouse. Just like the greenhouse, this layer of gas allows the Sun's rays to penetrate and then traps them, letting only a portion of the reflected rays escape back into the atmosphere and leading to a rise in temperature near the Earth's surface. Some cover of greenhouse gases is essential to ensure that the Earth's temperature stays habitable, but human activity, such as fossil fuel burning, have led to the concentration of some of these gases like CO2, which has risen above optimal levels, fueling global warming.
One major impact of this climate warming is the melting of glacial ice, which in turn results in sea level rise. This melting is exacerbated due to a phenomenon called the albedo effect. Albedo, derived from the Latin word, “albus”, meaning “white”, refers to the ratio of proportion of reflected to total solar radiation. This value will be close to one for fresh, white snow because it reflects most of the radiation. Bare soil, in contrast, has an albedo of only around 0.2, and open ocean only 0.1, and so these reflect significantly less - and so, as the climate warms, the snow melts, resulting in lower albedo, meaning that the Earth reflects less and retains more of the radiation as heat. This, in turn, causes the snow to melt more, creating a positive feedback loop and rising sea levels.
Another impact of climate change can be seen in species distribution. Species are found across a geographical area known as their range. As the climate warms, the resulting environmental changes, like melting ice caps, can cause a shift or decline in the habitable range of some of the species. Scientists have been studying these range shifts for different organisms in response to a variety of environmental variables. Using these data, they can model future changes in climate patterns and predict the likely fate of a species.
In this lab, you will assess greenhouse effects on an artificial microclimate, compare melting ice in different conditions, and study historical species' range shifts following environmental change.
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Q1: What is the difference between weather and climate?
Weather describes atmospheric conditions like temperature in a region over a short period, such as a day. Climate records the same conditions for the same region but over an extended period, such as average annual temperature. Global climate refers to these variables analyzed and compiled across the entire planet.
Q2: How do greenhouse gases cause global warming?
Greenhouse gases like carbon dioxide, water vapor, ozone, and methane form a layer around Earth similar to a glass shield. This layer allows the Sun's rays to penetrate but traps reflected rays, preventing them from escaping into space. This trapping of heat at Earth's surface due to the atmosphere is called the greenhouse effect, leading to rising temperatures.
Q3: What is the albedo effect and how does it accelerate ice melting?
Albedo is the ratio of reflected to total solar radiation, ranging from 0 to 1. Fresh white snow has high albedo around 0.8, while bare soil has only 0.2 and open ocean 0.1. As climate warms and snow melts, albedo decreases, meaning Earth reflects less radiation and absorbs more heat, creating a positive feedback loop that causes more melting.
Q4: How does sea level rise threaten coastal communities?
Melting glacial ice from warming temperatures causes sea levels to rise. Large ice sheets contain mass equivalent to nearly 70 meters of global sea-level rise. If ocean levels rise just 1 meter, significant portions of coastlines like Florida would be underwater, affecting millions of people's homes and destroying coastal properties.
Q5: What are species range shifts and why do they matter?
Species are found across a geographical area called their range. As climate warms, environmental changes like melting ice caps can shift or decline a species' habitable range. Scientists study these range shifts to predict whether species can adapt to changing temperature and precipitation patterns, or face extinction if they cannot move to suitable areas.
Q6: How does ocean acidification affect marine organisms?
Oceans absorb about a quarter of atmospheric carbon dioxide annually. When CO2 is absorbed by seawater, it converts to carbonic acid, making seawater more acidic and reducing carbonate ion availability. This hinders calcium carbonate structures in bivalves, sea urchins, and corals, combined with rising ocean temperatures, making aquatic ecosystems increasingly vulnerable.
Q7: Why is studying species extinction rates important for understanding climate change?
The extinction rate in the past century has been 1000 times greater than background rates, a phenomenon called the Holocene Extinction or Sixth Extinction. Habitat loss and climate change both drive species extinction. Understanding extinction patterns helps scientists recognize the urgent need to maintain environmental considerations in management decisions to mitigate climate impacts.