What is the escalator to extinction?
The earth is currently facing its 6th Mass extinction event. Which for the first time in the world’s history has been caused by one species, humans. To run our modern society we are rapidly changing our world. By modifying our land and by pumping greenhouse gases (GHGs) into the atmosphere to make everything we use daily.
What is the world current average temperature and CO2 concentration?
CO2 Concentrations
On the 2nd of August 2024 the current Global CO2 amount was at 422.93ppm (parts per million) This means for one million particles of air there is 422.93 particles of carbon dioxide found.
Global Temperature
According to NASA in 2023, earths average temperature was 1.17 °C. With earths average temperature being 1.36 °C warmer than the average from pre-industrial period.
Paris Agreement Targets
The Paris Agreement is trying to keep earths average warming below 2 °C above pre-industrial levels. But first they are actively trying to limit warming to 1.5 °C above pre-industrial levels.
Biodiversity Loss
We are losing biodiversity at alarming rates with 1,000,000 species currently threatened with extinction according to the UN. WWF estimates that human impacts have increased the extinction rate between 1,000 and 10,000 times more than natural extinctions.
One of the most frightening things about global warming is how the world’s biomes are shifting to get away from the warming climate. By moving poleward and higher in altitude. So, even if we didn’t disturb species in their natural habitats, global warming is still driving populations to extinction.
Keywords to Understand
What are RCPs (Representative Concentration Pathways)
RCP graphs are used to predict how four different amounts of GHGs are released into the atmosphere over time. These four are RCP 2.6, 4.5, 6.0 and 8.5. The number represents how much heat-trapping potential the GHGs have caused in the atmosphere. You can think of each RCP curve as 2.6 being the best we can do to reduce our emissions from the current situation. 4.5 being a low increase in emissions. 6.0 being a medium increase in emissions. Lastly 8.5 is a high increase in emissions or “business as usual” if we don’t do anything to reduce emissions.
This current decade is the divergence point of these four RCPs. So what we do now will be critical for determining what the future of the world will look like.
What are Abiotic and Biotic factors?
Abiotic Factors
Abiotic is all the non-living chemical and physical parts that help make up specific characteristics of an ecosystem. Some examples are temperature, elevation, latitude, type of soil, air, water, salinity, precipitation, humidity, wind and nutrients.
Biotic Factors
Biotic factors are all living organisms in an ecosystem. Which can contain a mix of any animals, plants, bacteria, fungi and protists species.
What is an Ecosystem?
An ecosystem is a community of biotic and abiotic factors all linked together with energy flows and nutrient cycles. Which creates a system where every part plays a role.
What are Nutrient Cycles?
A nutrient cycle is nutrients moving around an ecosystem from abiotic to biotic factors. For example, nitrogen moves from the soil (abiotic) to plants (biotic) and when plants lose their leaves some of the Nitrogen goes back into the soil.
What are Energy Flows?
Energy flows is energy coming from the sun and plants photosynthesising the energy and then other animals eat plants to create a cycle of energy movement e.g. herbivores and carnivores.
What are Biomes?
A biome is a large area on earth that we categorize based on the unique mix of abiotic and biotic factors found there. Precipitation and temperature are the main factors determining the location of biomes.
For example, rainforests are found around the equator where there is high amounts of rainfall, humidity and temperature. This creates the perfect conditions for a high biodiversity of organisms from frogs to butterflies to flowers.
What are the types of Biomes in the World?
There are eight terrestrial biomes in the world. These are tropical rainforests, temperate deciduous forests, savanna, deserts, grassland, mediterranean, northern coniferous forests and tundra.
There are two main types of aquatic biomes in the world, freshwater and saltwater. We can further split these into lakes, ponds, rivers and streams, wetlands, mangroves, estuaries, coral reefs, seas and oceans.
What is the difference between Biomes and Ecosystems?
We define an ecosystem as a small-scale interaction between abiotic and biotic factors. Characterized by nutrients that flow through the ecosystem. There can be many ecosystems in a biome. Biomes are large spanning many countries and even continents and they can have many ecosystems in them.
What is happening to our Biomes?
The Escalator to Extinction is also known as the Escalator effect.
As the climate changes and the world warms, the average temperature of biomes changes. For example, the average temperature of arctic tundra in the Northern Hemisphere may be somewhere between -34 to -6 degrees Celsius currently. Another example would be tropical rainforests which on average are between 20 and 29 °C. With Climate change these average biome temperatures are predicted to increase.
Changing the temperature can alter other abiotic factors in the biomes. Especially increases in the frequency of rain and storm events. Altered abiotic factors can shift the defining features of a biome. The increase in temperatures doesn’t suit the animals and plants in the ecosystems. This means they are now gradually moving poleward and increasing in altitude to get away from the warming temperatures. As they cannot adapt fast enough to stay in their current habitats. This results in biomes shifting closer and closer to the poles and away from the equator.
Examples of Escalator to Extinction
An example of the escalator to extinction is a mountain. Forest may dominate the bottom of the mountain, followed by shrubland, herb fields, grasses and then rock and snow at the top. As the temperature increases, these plant species need to move upward to find their ideal temperature range. Once a mountain peaks those species at the top have nowhere to go, resulting in the extinction of those high-altitude plant and animal species from that mountain.
Now think of the world and the general pattern of biomes, starting from the equator and working our way towards the poles. We have tropical rainforests on the equator, deserts and grasslands, temperate forests, boreal forests, tundra and then the ice caps of the poles. As these biomes shift away from the equator, the first biome to be affected will be the artic tundra as boreal forests invade. Which may lead to the extinction of the tundra biome over time.
This study talks about extinction risks because of climate change. It shows that 15-37% of species in the regions of the study will be at risk of extinction. With a mid-range climate warming scenario. Mid-range in this study is an increase in global temperatures of 1.8-2.0 °C and CO2 atmospheric concentrations of 500-550 parts per million in volume.
3 Examples of Species on the Escalator to Extinction
Tropical Bird Species
In this study, they looked at how climate change has affected five tropical bird populations in the mountains of Cerro de Pantiacolla, Peru. They discovered that the bird’s highest habitat range had shifted up, increasing in altitude, because of global warming. Researchers found that species living on mountaintops were the most affected by warming. Some populations lost their whole habitat, while others disappeared from the mountains.
The scientists found three main reasons why mountain top species are more vulnerable to climate change. First, they have nowhere to go as their once suitable habitat isn’t ideal. This is what I was talking about above in terms of when mountains peaks the habitat decreases. As there is only so much space a population can move up a mountain. Secondly, because these mountains are in the tropics they may not have cooler peaks, which the species can move to. Finally, tropical species may be less able to adapt to temperature changes than species in other regions.
Mountains have high amounts of endemism, which means they have lots of species found nowhere else in the world. Losing these species will result in losing a specific part of the world’s biodiversity.
Checkerspot Butterfly
This study looks at the checkerspot butterfly found in North America. It shows how an increase in temperatures is causing populations to ascend mountains. Warming increases the risks for this species as it causes a mismatch between the butterflies and its host plant.
Study populations have been increasing in elevation over time. Which has led to the butterflies switching to a new host plant. The butterflies are currently adapting to these changes, but the current range will become unsuitable for them to live.
This means conservation efforts will have to involve moving the populations to new areas. This new approach to protecting species affected by climate change could help other species in the future.
Pika
Another study looks at warming effects on Pika populations found in Western North America. Two types of Pika populations observed in this study: Isolated populations and Mainland populations.
Climate, especially temperature and water balance has strongly driven the loss of Pika populations in isolated areas compared to mainland populations. Water balance is the balance of water going in and out of a river system.
Habitat availability is a stronger driver in the continuation of mainland Pika populations compared to isolated ones. They found that Pika will live in a warmer climate if there is enough good habitat for the population. But climate change is most likely going to cause more population extinctions of Pika especially in isolated regions. Conservation efforts should look at protecting existing habitats and looking at potential refuges for Pika.
Another paper looked at Pika in the Northern Rocky Mountains. Warmer summer and winter temperatures led to fewer Pika sightings, and where they did spot them the populations were smaller. The increase in temperatures saw Pika moving up mountains into higher elevations an average of 281m. The larger the habitats with ideal moisture levels were better for the Pikas.
Thank You for Reading!
I hope you found this interesting, learning about the escalator to extinction and where its already happening right now. Global warming causes this issue, so by working together to decrease our GHGs we have a chance of halting the escalator. So we can stop species and biomes from being lost forever. If you want a blog post on ways to reduce our GHGs let me know in the comments.
Thank you for reading!! I just want to finish by saying I don’t want to scare you with this information. I want you to be able to understand the science and use this to create positive change in your life. No matter how big or small your changes are, it will all help protect our beautiful world for generations to come. Because if we all work together, we can make a massive difference.
Georgia xo
