The most widely accepted cause of global warming is the rising concentrations of two greenhouse gases – carbon dioxide and methane – in the atmosphere. Although these gases are naturally found in the Earth’s atmosphere, recent activities by humans have caused their concentrations to rise significantly, leading to the trapping of solar radiation and a rise in the average global temperature.
Carbon dioxide is produced primarily by burning fossil fuels (oil, coal, and natural gas) and through the burning of biomass. The combustion of these materials releases carbon dioxide (CO2) into the atmosphere, where it accumulates and traps heat. Carbon dioxide emissions from fossil fuel combustion account for over 80 percent of total global emissions, and the effects are far-reaching and long-lasting. Carbon dioxide stays in the atmosphere for hundreds of years, meaning that it has built up due to past and present emissions, leading to a “long-term climate forcing”. Furthermore, carbon dioxide’s ability to absorb and reflect heat increases over time: the more there is in the atmosphere, the more it warms the planet.
Methane is another significant greenhouse gas that contributes to global warming. Methane is released into the atmosphere as a result of many human activities, including the extraction and use of fossil fuels, livestock farming, and landfills. Methane has a more intense absorbed infrared radiation than carbon dioxide – meaning that it is a particularly potent greenhouse gas. In fact, the quantity of energy released by each molecule of methane is roughly 25 times more than a molecule of carbon dioxide, despite the fact that it is present in much lower concentrations. Methane also breakthroughs relatively quickly, in around a decade, which means that emissions need to be continually managed in order to ensure that temperature level don’t rise.
Indeed, reducing the emissions of carbon dioxide and methane is essential for preventing the most adverse impacts of global warming. The Paris Agreement sets the ambition to limit global warming to 1.5°C above pre-industrial levels, and this requires significant cuts in the emissions of these two gases. Carbon dioxide and methane are both still extracted and used for modern life, as well as natural sources, so it is important that we better understand and manage their concentrations in the atmosphere to minimize the harmful effects of global warming.
What’s more, capturing and storing carbon dioxide from the atmosphere and market-based solutions, such as carbon taxes and emissions credits, could help reduce its emissions. Similarly, methane reduction is possible through the implementation of better animal husbandry practices, improved manure management, and the identification of new technologies that are more efficient in the handling of agricultural waste. Ultimately, it is important to remember that without reducing emissions of both carbon dioxide and methane, the goal of limiting global warming to 1.5°C may not be achievable.
The impacts of global warming are becoming increasingly visible, from weather extremes and higher average temperatures to sea level rise and reduced crop yields. It is becoming clearer that global warming is caused by human activities, particularly the excessive extraction and use of carbon dioxide and methane in particular. Despite the seriousness of this issue, there are a range of available measures that, if implemented, could help to reduce the concentrations of these two gases in the atmosphere and minimize the effects of global warming.
The challenge of tackling global warming is vast, requiring widespread investment and the collaboration of international leaders. If we are to climb this mountain and hope to limit global warming to 1.5°C, now is the time to take bold steps and enact the policies and technologies necessary to reduce emissions of carbon dioxide and methane, the two major contributors to global warming.
