Climate Change
Part 2
Impact of Climate Change
- Climate change can affect our health, ability to grow food, housing, safety and work.
- Some of us are already more vulnerable to climate impacts, such as people living in small island nations and other developing countries.
- Conditions like sea-level rise and saltwater intrusion have advanced to the point where whole communities have had to relocate, and protracted droughts are putting people at risk of famine.
- Some changes (such as droughts, wildfires, and extreme rainfall) are happening faster than scientists previously assessed.
- In fact, according to the Intergovernmental Panel on Climate Change (IPCC) modern humans have never before seen the observed changes in our global climate.
- They also predict that some of these changes are irreversible over the next hundreds to thousands of years.
Environmental effects:
- Since the 1950s, droughts and heat waves have appeared simultaneously with increasing frequency.
- The rainfall rate and intensity of hurricanes and typhoons is likely increasing.
- Global sea level is rising as a consequence of glacial melt, melt of the ice sheets in Greenland and Antarctica, and thermal expansion.
Tipping points and long-term impacts:
- Greater degrees of global warming increase the risk of passing through ‘tipping points’—thresholds beyond which certain impacts can no longer be avoided even if temperatures are reduced.
- Some large-scale changes could occur over a short time period, such as a shutdown of certain ocean currents like the Atlantic Meridional Overturning Circulation (AMOC).
- Tipping points can also include irreversible damage to ecosystems like the Amazon rainforest and coral reefs.
Nature and wildlife:
- Higher atmospheric CO2 levels and an extended growing season have resulted in global greening.
- However, heatwaves and drought have reduced ecosystem productivity in some regions.
- The oceans have heated more slowly than the land, but plants and animals in the ocean have migrated towards the colder poles faster than species on land.
- Ocean acidification makes it harder for organisms such as mussels, barnacles and corals to produce shells and skeletons; and heatwaves have bleached coral reefs.
- Harmful algal blooms enhanced by climate change and eutrophication lower oxygen levels, disrupt food webs and cause great loss of marine life.
Humanity:
- Between 1.5 and 2.5 billion people live in areas with regular water security issues. If global warming would reach 4 °C, water insecurity would affect about twice as many people.
- A 2018 study found that potential global economic gains if countries implement mitigation strategies to comply with the 2 °C target set at the Paris Agreement are in the vicinity of US$17 trillion per year up to 2100 compared to a very high emission scenario.
- Wealthy countries in colder regions have either felt little overall economic impact from climate change, or possibly benefited, whereas poor hotter countries very likely grew less than if global warming had not occurred.
- One study found a 3.5% reduction in global GDP by the end of the century if warming is limited to 3 °C, excluding the potential effect of tipping points.
- The effects of climate change are often interlinked and can exacerbate each other as well as existing vulnerabilities.
- The impacts are often exacerbated by related environmental disruptions and pressures such as pollution and biodiversity loss.
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