CO2 emissions primarily stemming from human activities pose a global challenge in the fight against climate change.
The main focus of the ongoing negotiations at the COP26 summit in Glasgow revolves around carbon dioxide (CO2), a greenhouse gas released when fossil fuels such as coal, oil, and natural gas are burned, along with factors like wildfires and land use.
The industrial revolution in the late 1800s began to drive fossil fuel combustion. It provided crucial energy for industries but also significantly increased CO2 emissions even within that century. Systematic measurements since the mid-1900s have shown a steady rise in CO2 levels in the atmosphere, largely attributable to the burning of fossil fuels.
Chart showing the increase in CO2 density in the atmosphere from 1960 to 2020. (Photo: NOAA)
Why Does CO2 Cause Climate Change?
When released into the atmosphere, CO2 tends to accumulate for a very long time. Only half of it is absorbed by plants and oceans, while the other half can persist for hundreds of years in the atmosphere, contributing to the greenhouse effect.
Here’s how the greenhouse effect works. Our Sun sends a vast amount of energy to Earth. The Earth absorbs that energy and emits infrared radiation back into space. The accumulation of CO2 in the atmosphere traps some of that radiation, causing our planet to warm. The higher the CO2 density, the greater the increase in global temperatures. Currently, CO2 levels in the atmosphere are around 414 ppm, nearly one and a half times the 280 ppm level during pre-industrial times.
In 2020, when fewer people were driving and some industries had to temporarily shut down due to the pandemic, CO2 emissions from fossil fuels decreased by about 6%. However, this did not prevent the increase in CO2 density in the atmosphere, as emissions from human activities far exceeded what nature could absorb.
Even if the world stopped all CO2 emissions, it would take hundreds of years for atmospheric CO2 levels to decrease “naturally” to a threshold where the planet’s carbon cycle could return to a balanced state.
Chart reflecting and predicting CO2 density in the atmosphere before and after 2021. (Photo: Pieter Tans)
How Has Temperature Increased Across Continents?
It is no surprise that the world has recorded temperature increases across all continents and oceans. However, the rate of increase varies in different places due to numerous factors affecting local temperatures, such as land use (which affects the amount of solar energy absorbed and reflected) and local heating sources like urban heat islands and pollution.
For example, the Arctic is warming about three times faster than the global average, partly because as the planet warms, melting ice and snow leave surfaces more likely to absorb energy rather than reflect solar radiation.
Chart reflecting temperature increases and decreases across continents and oceans. (Photo: NOAA)
What Impact Does Climate Change Have on the Planet?
The Earth’s climate system is intricately interconnected, so even small temperature changes can have significant impacts, such as melting ice and rising sea levels.
Studies have shown that rising temperatures affect precipitation, glaciers, weather patterns, tropical cyclone activity, and severe storms. Heatwaves are also increasing in frequency, duration, and intensity, affecting ecosystems, human lives, commerce, and agriculture.
Most sea level records show a consistent increase over the past 150 years due to melting ice and ocean expansion. Rising sea levels exacerbate coastal flooding.
Climate scientists are working diligently to predict future impacts caused by increasing CO2 emissions and other anticipated changes, such as global population growth. It is clear that temperatures will rise and precipitation patterns will change. The specifics will depend on many interacting factors.
Predicted temperature increases for the period 2081-2100 compared to 1995-2014. (Photo: Claudia Tebaldi, et al., 2021).
A Few Reasons for Hope
One positive aspect is that scientific research is continuously enhancing our understanding of the climate and the complex systems of Earth, helping to identify the most vulnerable areas and providing guidance for mitigating climate change drivers.
Research into renewable energy and alternative energy sources, as well as solutions for capturing carbon from the atmosphere, is creating more options for a better-prepared society.
At the same time, as personal awareness increases, more individuals are seeking ways to reduce their own impact. The electric vehicle market, along with solar and wind energy, is growing at an astonishing rate. More people are willing to adopt new strategies for energy efficiency and more sustainable consumption.
Scientists believe that transitioning from fossil fuels to renewable energy is key to combating climate change, offering direct benefits for human health and ecosystems.
