Climate change is adversely impacting global ecosystems through its worsening trends and through climate-driven hazards. The range of trends includes creeping atmospheric, land, and ocean temperatures, sea level rise, ocean acidification, deforestation, the loss of biodiversity, desertification, and coastal erosions. Climate-driven hazards include heat waves, wildfires, floods, coastal storms, and droughts.
Ecosystems are made up of the plants, animals, people, and other living things that interact with the physical environment around us. Ecosystems provide us food, clean water, air, and other natural materials that are vital to our lives. They are also sources of human recreation, mental well-being, and protection from natural hazards. However, ecosystems are experiencing numerous human-induced threats; climate change being one of them. Many ecological threats exist independently of climate change. However, climate change has been shown to amplify the effects of natural hazards, causing greater ecological degradation, potentially exacerbating tensions among countries competing for natural resources. Conversely, ecosystems can assist in the mitigation of, and adaptation to, climate change. For example, forest ecosystems are the largest terrestrial carbon sink on Earth, and afforestation and reforestation have been recognized as cost-effective strategies for reducing atmospheric greenhouse gases.
The Ecological Threat Report (ETR), published by the Institute for Economics and Peace (IEP), is a comprehensive, data-driven analysis covering over 2,500 sub-national administrative units in 178 independent countries and territories. It covers 99.9% of the world’s population and assesses ecological threats in five areas: food risk, water risk, population pressures, climate change, and natural disasters.
The latest Intergovernmental Panel on Climate Change (IPCC) report projects that climate change will bring worse fires, longer droughts, and more severe floods. The 2021 ETR states that, with the number of natural disasters tripping over the last four decades, both undernourishment and food insecurity have been steadily rising since 2015. This is the reversal of a long-term trend where undernourishment had been improving. High population growth, lack of clean water, and increasing land degradation are clear contributors. IEP projects the number of undernourished people to rise by 343 million people by 2050, to 1.1 billion. This is a 45% increase.
According to ETR (figure below), the most common catastrophic threat is water risk. In total, water risk is the highest scoring threat for 49 countries. This is followed by temperature anomalies and food risk.
This report also identifies regions and countries most at risk of ecological failure and socioeconomic collapse (figure below). These countries are currently facing hardship and instability, even without the effects of climate change. In the high-risk regions, rapid population growth, coupled with environmental degradation and climate change, have increased the exposure to and risk of natural hazards. This will result in more frequent, intense, and costly disasters.
Afghanistan (in the South Asia region) scores extremely high in all risk indicators in the 2021 ETR; its highest average score is water risk. Climate change poses a threat to Afghanistan’s natural resources, and the alternation of floods and droughts is expected to impact agricultural productivity and output. Furthermore, ongoing political conflicts have undermined Afghanistan’s capacity to cope with ecological threats.
The ETR report analyzes terrestrial ecological threats only. But the oceans are a collection of many types of ecosystems and marine ecological threats can be devastating to coastal and island communities around the world. The ocean absorbs about 30% of the CO2 that is released into the atmosphere. According to the U.S. National Ocean Service, the pH (a measure of acidity in liquids) of surface ocean waters has fallen by 0.1 pH units for the past 30 years (the blue line in the figure below). This might not sound like much, but the pH scale is logarithmic, so this change represents approximately a 30% increase in acidity. When CO2 is absorbed by seawater, a series of chemical reactions occur resulting in the increased concentration of hydrogen ions. A more acidic environment has a dramatic effect on some calcifying species, including oysters, clams, sea urchins, shallow water corals, deep sea corals, and calcareous plankton. When shelled organisms are at risk, the entire marine food web, and thus fisheries, may also be at risk.
