| All people on Earth depend directly or indirectly on the ocean and cryosphere. The global ocean covers 71% of the Earth surface and contains about 97% of the Earth's water. The cryosphere refers to frozen components of the Earth system. Around 10% of Earth's land area is covered by glaciers or ice sheets. The ocean and cryosphere support unique habitats, and are interconnected with other components of the climate system through global exchange of water, energy and carbon. |
| Human communities in close connection with coastal environments, small islands, polar areas and high mountains are particularly exposed to ocean and cryosphere change, such as sea level rise, extreme sea level and shrinking cryosphere. Other communities, further from the coast are also exposed to changes in the ocean, such as through extreme weather events. |
| In addition to their role within the climate system, such as the uptake and redistribution of natural and anthropogenic carbon dioxide and heat, as well as ecosystem support, services provided to people by the ocean and/or cryosphere include food and water supply, renewable energy, and benefits for health and well-being, cultural values, tourism, trade, and transport. |
| Over the last decades, global warming has led to widespread shrinking of the cryosphere, with mass loss from ice sheets and glaciers, reductions in snow cover and Arctic sea ice extent and thickness and increased permafrost temperature. |
| Over the last century some species of plants and animals have increased in abundance, shifted their range, and established in new areas as glaciers receded and the snow-free season lengthened. Together with warming, these changes have increased locally the number of species in high mountains, as lower-elevation species migrate upslope. |
| Some cold-adapted or snow-dependent species have declined in abundance, increasing their risk of extinction, notably on mountain summits. In polar and mountain regions, many species have altered seasonal activities especially in late winter and spring. |
| Increased wildfire and abrupt permafrost thaw, as well as changes in Arctic and mountain hydrology have altered frequency and intensity of ecosystem disturbances. This has included positive and negative impacts on vegetation and wildlife such as reindeer and salmon. |
| Since about 1950 many marine species across various groups have undergone shifts in geographical range and seasonal activities in response to ocean warming, sea ice change and biogeochemical changes, such as oxygen loss, to their habitats. This has resulted in shifts in species composition, abundance and biomass production of ecosystems, from the equator to the poles. Altered interactions between species have caused cascading impacts on ecosystem structure and functioning. In some marine ecosystems species are impacted by both the effects of fishing and climate changes. |
| Coastal ecosystems are affected by ocean warming, including intensified marine heatwaves, acidification, loss of oxygen, salinity intrusion and sea level rise, in combination with adverse effects from human activities on ocean and land. Impacts are already observed on habitat area and biodiversity, as well as ecosystem functioning and services. |
A) Their risk of extinction has increased
B) They have altered their seasonal activities
C) Both (a) and (b)
D) Neither (a) nor (b)
Correct Answer: C
Solution :
(c) Some cold-adapted or snow-dependent species have declined in abundance, increasing their risk of extinction, notably on mountain summits. In polar and mountain regions, many species have altered seasonal activities especially in late winter and spring.
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