2. Climate Change
• The Earth's temperature had already warmed by 1°C compared to pre-industrial levels. This temperature rise may
appear small, but small rises in temperature translate into big changes for the world’s climate. This is because the
amount of extra energy needed to increase the world’s temperature, even by a little, is vast. This extra energy is
like force-feeding the global climate system.
• • Hotter days:
2015 was the hottest year on record, the previous record was broken in 2014, and 2016 is expected to set a new
record for the third year in a row. In the past few years records have being broken for longest heatwaves and the
Bureau of Meteorology has added purple and magenta to the forecast map for temperatures up to 54°C.
•
• • Rising sea levels:
Increased ocean temperatures are melting glaciers and ice caps all over the world. Melted ice increases the
volume of water in our oceans. Warmer temperatures also result in the expansion of the water's mass, which
causes sea levels to rise, threatening low-lying islands and coastal cities.
•
• • More frequent and intense extreme weather events:
Extreme weather events like bushfires, cyclones, droughts and floods are becoming more frequent and more
intense as a result of global warming.
•
• • Oceans are warming and acidifying:
• The oceans have absorbed most of extra heat and carbon dioxide (CO2) so far – more than the air – making the
seas both warmer and more acidic. Warming waters are bleaching coral reefs and driving stronger storms. Rising
ocean acidity threatens shellfish, including the tiny crustaceans without which marine food chains would collapse.
•
3.
4. Glaciers melt down
• Most of Earth's glaciers are melting faster than ever because of
human-caused climate change, dumping about 328 billion tons of
melted ice into the world's oceans each year, according to a new
study.
• In fact, what was once considered to be permanent ice has declined
in volume almost everywhere around the globe, the study found.
• Half the world’s glacial loss is coming from the United States and
Canada, the study said.
• Alaska’s melt rates are “among the highest on the planet,” with the
Columbia glacier retreating about 115 feet a year, said study lead
author Romain Hugonnet, a glaciologist at the University of
Toulouse in France.
• The estimates were based on high resolution 3D mapping of more
than 200,000 glaciers, which is nearly all the glaciers on Earth. The
analysis is the most comprehensive and accurate of its kind to date.
5.
6. Soil degradation
• Soil is the biggest terrestrial carbon sink. The world’s soils store more carbon than
the planet’s biomass and atmosphere combined. This includes soil organic carbon,
which is essentially biodiversity: microbes, fungi and invertebrates, as well as root
matter and decomposing vegetation. Soil carbon stocks can be increased through
appropriate land management to provide many benefits besides offsetting
greenhouse gas emissions.
• Loss of soil organic carbon is one of the principal signs of land degradation, and
land degradation is one of the leading challenges for sustainable development,
biodiversity conservation, and mitigating and adapting to climate change. It is
defined as a reduction or loss of the biological or economic productivity and
complexity of land. In drylands, land degradation is known as desertification.
• When land is degraded, soil carbon can be released into the atmosphere, along
with nitrous oxide, making land degradation one of the biggest contributors to
climate change. An estimated two-thirds of all terrestrial carbon stores from soils
and vegetation have been lost since the 19th century through land
degradation. Agriculture, forest and other land-use sectors generate roughly a
quarter of all anthropogenic greenhouse gas emissions.
7.
8. Endangerment of wildlife
• Habitat Disruption
• The key impact of global warming on wildlife is habitat disruption, in which ecosystems—places where animals
have spent millions of years adapting—rapidly transform in response to climate change, reducing their ability to
fulfill the species' needs. Habitat disruptions are often due to changes in temperature and water availability, which
affect the native vegetation and the animals that feed on it.
• Affected wildlife populations can sometimes move into new spaces and continue to thrive. But concurrent human
population growth means that many land areas that might be suitable for such “refugee wildlife” are fragmented
and already cluttered with residential and industrial development. Cities and roads can act as obstacles,
preventing plants and animals from moving into alternative habitats.
• Shifting Life Cycles
• Beyond habitat displacement, many scientists agree that global warming is causing a shift in the timing of various
natural cyclical events in the lives of animals. The study of these seasonal events is called phenology. Many birds
have altered the timing of long-held migratory and reproductive routines to better sync up with the warming
climate. And some hibernating animals are ending their slumbers earlier each year, perhaps due to warmer spring
temperatures.
• To make matters worse, research contradicts the long-held hypothesis that different species coexisting in a
particular ecosystem respond to global warming as a single entity. Instead, different species within the same
habitat are responding in dissimilar ways, tearing apart ecological communities millennia in the making.
• Which Animals Are Hardest Hit by Global Warming?
• According to Defenders of Wildlife, some of the wildlife species hardest hit by global warming include caribou
(reindeer), arctic foxes, toads, polar bears, penguins, gray wolves, tree swallows, painted turtles, and salmon. The
group fears that unless we take decisive steps to reverse global warming, more and more species will join the list
of wildlife populations pushed to the brink of extinction.
9.
10. Draught
• Global warming increases the risk of drought in several ways.
• For one, water generally evaporates more quickly at higher temperatures. For that reason, hotter
weather can result in drier soils. As high air temperatures sap liquid water from soils and plant
leaves, transforming it into atmospheric water vapor via a process called transpiration, ground-level
drying will increase in some regions. (Ironically, this additional atmospheric moisture triggers
heavier downpours in other regions, which explains why the overall trend in the U.S. has been
toward wetter conditions.)
• Higher air temperatures not only encourage drought conditions to build but also intensify them.
What might have otherwise been a mild or moderate drought in a cooler world will become, in a
warmer world, more severe as a result of increased evaporation.
• Warming also diminishes snowfall, an essential water resource for the estimated 1.9 billion
residents of the Northern Hemisphere who depend on snowpacks, or snow reservoirs that store
water during the cooler months and release it when it’s needed in the warmer, drier months. Rising
temperatures increase the fraction of winter precipitation that falls as rain rather than snow and
also shorten the cold season, so there’s less time for snow to even occur. Such was the case in
2015, the fourth-warmest year in the contiguous U.S., when a snow drought reduced the April
snowpack in the Sierra Nevada mountain range to a mere 5% of its historical average water content
— its lowest snowpack in 500 years.
• Seasonal melting of snowpacks can be thrown off-kilter, too. As average temperatures warm above
freezing earlier in the spring, snowmelt occurs sooner and faster than usual. And rapid melting
results in a shorter period during which soils and plants are kept moist.
11.
12. Acid rain
• Normally, rainwater is good for people, forests, crops, rivers
and lakes. Rain water is slightly acidic with a pH of 5.6. Acid
rain has been occurring for millions of years but with the
industrial revolution of the 1 700s and the advent of coal
burning, rainwater has become increasingly acidic.
• Sulphur dioxide (SO2), Nitrogen dioxide (NO2) and even
carbon dioxide (CO2) dissolve in rainwater to form dilute
acids.
• Acid rain harms trees and crops and upsets the balance of
life in lakes and rivers. A lake that becomes too acidic looks
crystal cleareven if it is lifeless. First, the aquatic plants are
killed. The absence of these plants depletes oxygen sources
for fish and amphibians. Acid rain does not kill the forest
itself but makes it susceptible to insects and diseases.