Impacts of Climate Change
Each of the last three decades has been successively warmer than any other preceding decade (Met Office) and all 16 years of the twenty-first century rank among the 17 warmest years on record. In England, average temperatures are between 0.5°C and 1°C higher than they were in the 1970s (Committee on Climate Change).Though warming has not been uniform across the planet, the upward trend in the globally averaged temperature shows that more areas are warming than cooling (NOAA).
The impact of extra heat for our planet
Since the late 19thCentury, the planets average surface temperature has increased by approximately 1°C. W still have the chance to limit global temperatures to below 2°C if we take urgent action. However, if no action is takenglobal temperatures could rise to beyond 7°C or more.
The oceans have absorbed 90% of this increased heat. (Only about 1% of the remaining heat is stored in the atmosphere, the rest heats the land and ice- ECIU). Global sea level has risen by 20cm on average around the world since the late 19thCentury:
- Ocean water also expands as it warms, contributing further to sea level rise.
- Increasing temperatures melt glaciers and other ice, increasing the volume of water in the oceans.
Sea level is projected to rise another 1 to 4 feet by 2100.
Ocean Acidification is the result of more carbon dioxide being absorbed by oceans, resulting in oceans becoming progressively more acidic. The amount of carbon dioxide absorbed by the upper layer of the oceans is increasing by about 2 billion tonnes per year (Copenhagen Diagnosis), representing a 30% increase in acidity since pre-industrial times (NOAA). If emissions continue rising at their current rate, it is predicted that the ocean will become more acidic than it has been for 50 million years (ECIU).
Impacts of Ocean Acidification
Increased acidity inhibits shell growth of marine organisms such as mussels, lobsters, shrimp and even some species of fish. This will have impacts further up the food chain and also affect the human populations who rely on the harvesting of shellfish for their livelihoods.
Ocean acidification also poses a threat to coral reefs, which form some of the most biodiverse habitats in the ocean. Corals must extract calcium from the water to form their hard outer skeleton, which requires a specific pH. Ocean acidification therefore impacts the ability of corals to develop, and also impacts their ability to respond to damage caused by other human activities as a result of tourism for example.
Temperature changes in the ocean can also impact corals, causing them to ‘bleach’ which is when coral polyps expel the algae that lives inside of them due to higher temperatures. The coral turns completely white and is at risk of dying if the algae aren’t reabsorbed. Temperature increases of only 1-2 Celsius above normal during summer can induce bleaching.
Research from theU.N. Convention on Biological Diversity found that damage to reefs by the end of this century alone would cause an economic loss of $1 trillion annually.
You can read a full briefing on ocean acidification from ECIU here.
Data from NASA's Gravity Recovery and Climate Experiment show Greenland lost and average of 281 billion tons of ice per year between 1993 and 2016, while Antarctica lost about 119 billion tons during the same time period.
Global warming is likely to be the greatest cause of species extinctions this century (WWF). The Intergovernmental Panel on Climate Change says a 1.5°C average rise may put 20-30% of species at risk of extinction. Climate change is happening too quickly for species to adapt. Experts predict that one quarter of Earth’s species will be headed for extinction by 2050 if urgent action isn’t taken (The Nature Conservancy).
Changing rainfall patterns
There is evidence that rainfall patterns are changing depending on location. For example, the Met Office reports that rainfall has increased in the mid-latitudes of the northern hemisphere since the beginning of the 20th century. There are also seasonal changes. For example the UK's summer rainfall is decreasing on average, while winter rainfall is increasing and heavy rainfall events have become more intense.
Climate change projections
Greenhouse gas emissions are likely to continue rising and therefore further climate change is also likely. Once in the atmosphere, carbon dioxide can continue to affect the climate for 100 years or more, meaning it has a very long time to build up and affect our climate. Some of the CO2 in our atmosphere was emitted before World War I.
The IPCC has identified a range of concerns for the future, including:
- Increased likelihood of extreme weather events
- Worsened impacts on the world’s poorest and most vulnerable populations
- Both environmental and economic damage
- Large scale events such as sea level rise and the melting of entire ice sheets.
Date of Publication: 5.07.2018