Day-to-day, weather varies depending on factors like region, elevation, temperature, precipitation, wind flow and time of year. But in the background of daily weather variations, changes that happen over decades or longer can be observed in weather records. These decadal changes are the climate.
Information taken from ice cores, sediments, satellites and weather stations over years have all pointed to a changing climate. Today, the evidence is overwhelming- the planet’s average temperature is gradually increasing. The change in global climate is widely corroborated by the vast majority of actively publishing climate scientists. Most agree that the changes to our climate are markedly intensified by human activities, such as energy production, manufacturing and agriculture.
So called, ‘human-induced climate change’, or anthropogenic climate change has 5 distinct effects: 1) increased surface temperatures, 2) rising sea levels, 3) melting ice sheets, 4) declining biodiversity, and 5) decreased agriculture production.
Rising surface, ocean, and atmospheric temperatures, also known as global warming, is perhaps the most influential symptom of climate change. As average daily temperatures gradually increase, there may be more incidents of heatwaves and droughts. Global warming also adds to the likelihood of wildfire occurrences. Evapotranspiration-the combination of water evaporation, soil moisture evaporation, and plant transpiration-rids soils and vegetation of their moisture. Dried-out plant matter acts as kindling during wildfires and enables the spread of flames.
Extreme heat may also be hazardous to human health. People who are exposed to extreme heat can experience a range of conditions, including heat stroke, heat exhaustion, heat cramps, or heat rashes.
Sea Level Rise
Sea level rise is related to the melting of land-ice and thermal expansion in seawater caused by heating oceans. The most affected communities are those along coasts. Coastal systems are more sensitive to rising seas because of their low elevation and proximity to large bodies of water. Erosion from intense wave action and flooding threatens coastal infrastructure more than that of high-elevation and inland territories. On top of that, coasts are highly vulnerable to extreme storms such as tropical cyclones. Coastal storms, including hurricanes and tropical storms, generate powerful ocean waves and harsh winds that indiscriminately damage property and claim lives.
Melting Ice Sheets
Ice sheets are permanent masses of ice that cover vast amounts of land in Greenland and Antarctica. Under the influence of climate change, ice sheets melt more quickly. Water from melting land ice inevitably flows into seas and contributes to rising sea levels. In return, increasing amounts of melting sea ice loss reinforce global warming. This is because brightly colored snow and ice surfaces reflect sunlight back into space at a higher rate than the surfaces of darkly colored sea water, which are more efficient at absorbing sunlight and heat energy. As ice sheets melt, Greenland and Antarctica will continue to heat up, and vice versa.
Permafrost (layers of subsurface soil, gravel, and sand that stay frozen year-round) stores plant material and keep them from decomposing as long as they remain frozen. Thawing these icy structures will allow the natural breakdown of plant materials to take place. When organic materials decompose, an array of greenhouse gases such as methane and carbon dioxide are released into the atmosphere and intensify global heating.
A report published in 2021 by the Intergovernmental Panel on Climate Change (IPCC) and Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) drew a connection between climate change and biodiversity loss. According to the report, long-term climatological shifts have the potential to adversely alter a wide range of ecosystems.
For example, ocean acidification, which is driven by warming sea temperatures, can be harmful to species that form shells and skeletons from calcium and carbonate. When large amounts of atmospheric carbon dioxide are absorbed by seawater, the water’s pH is reduced and the amount of carbonate ions decreases. Ocean acidification can make shells and skeletons grow more slowly or dissolve more quickly, leaving species like scallops, corals, sea urchins, and clams more prone to impaired health.
Effects on Agriculture
The physical effects of climate change could be influencing agriculture production in a myriad of ways because crops depend on suitable environmental conditions to grow. Crop growth can be disturbed by abiotic stress like shifts in air temperature or lack of water. A 2017 study titled, “Temperature Increase Reduces Global Yields of Major Crops in Four Independent Estimates“, compiled results from four analytical methods (global grid-based models, local point-based models, statistical regressions, and field-warming experiments). They discovered that “without CO2 fertilization, effective adaptation, and genetic improvement, each degree-Celsius increase in global mean temperature would, on average, reduce global yields…”. For certain plant species, exposure to hotter temperatures could lower yields and make food security threats more pronounced in the future.