Much greater warming is projected if CO2 emissions continue to rise at their current rate. Climate models suggest that the world’s average temperature will rise in the future, but the degree of warming will be determined by our decisions on fossil fuel and land usage. If we continue to release the same amount of greenhouse gases that we did in the twentieth century, we will see substantially more warming in the twenty-first century. If greenhouse gas levels continue to grow, computer models project that global average temperature will rise 4° C (7.2° F) during the twenty-first century. Models predict that global average temperature will only rise by 1° Celsius (1.8° F).
Climate change is expected to affect different places in different ways. Temperature rises are predicted to be larger on land than over oceans and at high latitudes than in the tropics and mid-latitudes. Other features of climate, including rain, snow, and clouds, will (and are) alter due to rising temperatures. They’re also affecting the seas, life, ice, and the rest of the Earth’s ecosystem.
A faster rate of evaporation will result from a warmer average world temperature, forcing the water cycle to “speed up.” There will be more precipitation if there is more water vapor in the atmosphere. For each degree of warming, global average precipitation increases by 1% to 3%, implying that we can e expect more rain and snow in the future. Precipitation will increase by at least 1% by 2100, with a maximum rise of nearly 12%. Changes in precipitation, on the other hand, will not be evenly distributed. Some areas will receive more, while others may receive less.
Melting Snow and Ice
Snow and ice melt as the environment warms. Summer melting of glaciers, ice sheets, and other snow and ice on land is expected to outnumber winter precipitation by two. With the Arctic sea ice melting faster than the Antarctic sea ice, the amount of sea ice (frozen saltwater) floating in the Arctic Ocean and around Antarctica is predicted to decrease. Despite some ambiguity regarding the quantity of melting, the Arctic Ocean will most likely be ice-free by the end of the century.: (1) melting glaciers and ice sheets (land ice) add water to the oceans, rising sea level; and (2) ocean water expands as it warms, increasing volume and hence raising sea level. During the twentieth century, sea levels climbed by 10 to 20 cm (4 to 8 inches). While the exact size of each source’s contribution is unknown, thermal expansion and melting ice each contributed roughly half of the rise. According to models, the sea level will rise between 30 and 100 cm (12 to 39 inches) by 2100, depending on how much we can minimize climate change.
Acidic Ocean Water
The Earth’s oceans are expected to act as a climate change buffer by absorbing extra heat and CO2 from the atmosphere. In the near term, this is terrific news, but in the long run, it is worrisome. When carbon dioxide and seawater combine, a weak carbonic acid is formed. Since pre-industrial times, scientists believe this process has decreased the pH of the oceans by around 0.1 pH. By the year 2100, further acidification of 0.14 to 0.35 pH is projected. Marine species may be harmed by more acidic ocean water.
Impacts on Ocean Currents
As the climate warms, large-scale ocean currents known as thermohaline circulation, which are driven by changes in salinity and temperature, may be altered. Salinity can be affected by changes in precipitation patterns and freshwater flow into the oceans from melting ice. Currents may be disrupted by changing salinity and rising water temperatures. In a worst-case scenario, thermohaline circulation in some sections of the sea might be disturbed or possibly stopped off, causing significant climate change.
Changes in Severe Weather
Some climate scientists predict that as a result of global warming, hurricanes, typhoons, and other tropical cyclones will (or have already begun to) alter. The energy that propels these massive storms comes from warm ocean surface waters. Warmer waters are projected to increase the intensity of such storms in the future. Although there may not be more tropical cyclones in the future, some experts anticipate that the most solid and deadly storms will be more common. According to some scientists, there is already evidence of an increase in the most powerful storms. Others, however, are not convinced.
In global climate models, clouds are a bit of a wild card. Warmer global temperatures cause total evaporation rates to increase, resulting in more water vapor in the atmosphere and more clouds. Distinct types of clouds have different climate effects depending on their location. Some plants provide shade to the Earth, which helps to cool the environment. Others contribute to the greenhouse effect by trapping heat in water vapor and droplets. Scientists predict that a warmer globe would be cloudier, but they aren’t sure how the additional cloudiness will affect the climate system. Modeling the impact of clouds on the climate system is a hot topic in science right now.
Risks to Marine Life
Ocean ecosystems are already changing as the water warms, and they will continue to change as the water warms. Fish, for example, can migrate to environments with cooler water at higher latitudes. However, many marine animals that can’t swim elsewhere, such as kelp and corals, are in grave danger.
Risks to Life on Land
Many species of plants and animals’ geographic ranges will be affected by changes in temperature, precipitation, and seasonal timing, posing a hazard to life on land. Many species will become extinct if the geographic region in which they may survive shrinks, as they can only exist in habitats that meet their needs. If global warming is limited to 2° C, 18% of insects, 16% of plants, and 8% of vertebrate animals will lose more than half of their geographic distribution. However, if global warming is limited to 1.5° C, just 6% of insects, 8% of plants, and 4% of vertebrates are expected to lose more than half of their geographic distribution.
None of these tipping points are thought to be likely to occur in the coming decades. Nonetheless, the consequences of any of them are so severe, and the fact that we can’t stop them once they’ve started, that we must consider them when assessing the real hazards associated with climate change.