Why ocean acidification is called climate change's evil twin
What you need to know:
- The main drivers of ocean acidification are anthropogenic CO2 emissions from burning fossil fuels, deforestation, and industrial processes.
Ocean acidification is an urgent environmental challenge caused by rising atmospheric carbon dioxide (CO2) levels, mainly due to human activities. It involves a continuous decrease in the pH of ocean water, with profound implications for marine ecosystems and the communities that rely on them. When CO2 is absorbed by seawater, it reacts to form carbonic acid, resulting in lower pH levels and increased acidity in the oceans.
Since the Industrial Revolution - a period of major technological and economic change that transformed society from an agrarian economy to one based on industry and manufacturing - ocean pH has dropped from about 8.19 to approximately 8.05, representing a 30 per cent increase in acidity. Although this change may seem minor, it can significantly affect marine life.
The primary concern regarding ocean acidification lies in its effects on marine organisms, especially those that depend on calcium carbonate to form their shells and skeletons. They include corals, molluscs and certain plankton species. Ocean acidity decreases the availability of carbonate ions, which is crucial for these organisms, making it increasingly difficult for them to construct and maintain their structures. This physiological stress from lower pH levels can disrupt marine species' growth, reproduction and overall health.
Coral reefs, often called the "rainforests of the sea," are particularly at risk; their decline threatens biodiversity and adversely affects tourism and fishing industries dependent on healthy reef ecosystems.
Catastrophic
Ocean acidification has been referred to as "climate change's evil twin" because it intensifies many of the same issues associated with global warming and presents unique challenges. While climate change leads to rising ocean temperatures and altered weather patterns, ocean acidification directly threatens marine chemistry and biology.
The pace of acidification is alarming, estimated to be about 100 times faster than any natural changes over the past 650,000 years, indicating that human activities are dramatically altering ocean ecosystems at an unprecedented speed. These changes threaten individual species and entire food webs.
The long-term effects of ocean acidification on marine food chains could be profound and potentially catastrophic. Increasing acidity alters the fundamental chemistry that supports aquatic life, particularly organisms at the base of the food web, like phytoplankton and zooplankton.
Phytoplankton are vital as they are primary producers in marine ecosystems and convert sunlight into energy through photosynthesis. Ocean acidification can impair their ability to create calcium carbonate shells, essential for certain species. This decline diminishes their populations and affects their nutritional quality, making less energy available for higher trophic levels. Research indicates that as these primary producers struggle, cascading effects will ripple through the food chain, impacting fish populations and larger marine mammals that depend on them for sustenance.
The main drivers of ocean acidification are anthropogenic CO2 emissions from burning fossil fuels, deforestation, and industrial processes. Oceans have absorbed approximately one-third of the CO2 released into the atmosphere since the Industrial Revolution.
Other contributing factors include agricultural runoff and natural events like volcanic eruptions. However, these typically have less impact than human-induced changes. As CO2 levels continue to rise, so does the urgency for action to mitigate its effects on marine environments.
Different regions of the ocean experience varying levels of acidification due to factors such as geographical location, water temperature and local environmental conditions. Coastal areas often face higher rates of acidification compared to open ocean regions because they are influenced by freshwater runoff that carries nutrients and pollutants from land. This runoff can lead to localised increases in CO2 levels and subsequent acidification.
Warmer waters hold less dissolved oxygen and can amplify the effects of acidification on marine life. Regions with high biological activity, like upwelling zones where nutrient-rich waters rise to the surface, may also experience more pronounced effects due to natural CO2 release from decomposing organic matter. These regional differences underscore the complexity of ocean acidification as a global issue. In contrast, some areas may adapt better than others. However, the overall trend is troubling for marine ecosystems worldwide.
Efforts to combat ocean acidification include mitigation strategies to reduce CO2 emissions and adaptation measures designed to help marine ecosystems cope with changing conditions. International agreements such as the Paris Agreement seek to limit global warming by curbing greenhouse gas emissions. Research initiatives are underway to understand better how different species respond to varying acidity levels and temperature changes. This knowledge can guide conservation efforts and help develop strategies for restoring affected ecosystems.
Researchers study various types of ocean acidification like coastal acidification in areas where freshwater runoff from rivers mixes with seawater, often worsened by nutrient pollution from agriculture. This localised phenomenon can severely impact shellfish populations and other marine life thriving in these environments. Deep-sea acidification occurs at greater depths where CO2 accumulates due to natural processes like respiration from deep-sea organisms.
The implications of ocean acidification extend beyond ecological concerns to pose economic threats. Due to changing ocean chemistry, coastal communities that depend on fishing and tourism face potential fish stocks and coral reef health declines. As key species become less viable or disappear altogether, food security for millions could be compromised. Cultural practices and traditions tied to these environments may also be affected as marine ecosystems shift.
Recent studies call for immediate action before irreversible damage occurs within our oceans. The United Nations warns that without significant reductions in greenhouse gas emissions globally, we risk further accelerating this crisis with dire consequences for marine life and human communities worldwide.