IPCC Special Report on the Ocean and Cryosphere (SROCC)
Last updated on December 12, 2024 7:17 PM
- The IPCC approved and accepted Special Report on the Ocean and Cryosphere in a Changing Climate.
- IPCC SROCC report updates scientific literature available since 2015 (since 5th Assessment Report).
- SROCC summarises the disastrous impacts of warming based on current projections of global GHG emissions.
- SROCC was prepared as a part of an IPCC Panel decision in 2016 to prepare three Special Reports:
- Special Reports on Global Warming of 1.5 °C (SR1.5 – October 2018),
- Special Report on Climate Change and Land (SRCCL – August 2019 – See {Envi – CC – 19/08/09} Land use patterns and climate change), and
- Special Report on the Ocean and Cryosphere in a Changing Climate (SROCC – September 2019)
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IPCC Special Report on the Ocean and Cryosphere in a Changing Climate (SROCC)
- Today’s oceans are experiencing unprecedented conditions with increased temperatures, further ocean acidification, marine heatwaves and more frequent extreme El Niño and La Niña events.
- Communities that live in close connection with coastal environments, small island nations, polar areas and high mountains are particularly vulnerable to changes, such as rising sea levels and shrinking glaciers.
- But communities in other areas are affected through extreme weather events exacerbated by ocean warming.
Ocean warming
- The global ocean has taken up more than 90% of the excess heat in the climate system.
- Since 1993, the rate of ocean warming has more than doubled.
- Marine heatwaves have very likely doubled in frequency since 1982 and are increasing in intensity.
- The ocean is warming, becoming more acidic and losing oxygen.
- The rising temperatures are starving the upper layers of the water of oxygen, suffocating marine life, creating growing dead zones, and disrupting the circulation of ocean currents (more disruptive weather on land).
- Long lag times at work in oceans mean that some of these changes will inevitably intensify over centuries — even if the world stopped emitting all its greenhouses gases tomorrow.
Sea Level Rise
- The sea levels are rising because of thermal expansion of ocean waters due to rising temperatures as well as due to melting of glaciers and polar ice.
- Globally sea levels are estimated to rise 1.1 metre by 2100, if countries are not able to restrict emissions “well below” 2 degrees Celsius above pre-industrial levels, as stated in the 2015 Paris climate agreement.
- But, even if countries are able to restrict emissions, it is still estimated to rise 30-60 centimetres by 2100.
- Fifty per cent of coastal wetlands have been lost over the last 100 years.
Cryosphere
- Between 2006 and 2015, the Greenland ice sheet lost ice-mass at an average rate of 278 billion tonnes every year, while the Antarctic ice sheet lost a mass of 155 billion tonnes on an average every year.
- Snow over areas outside of these two regions, like the glaciers in the Himalayas, together lost an average of 220 billion tonnes of ice every year.
- In the Himalayas, glaciers feeding 10 rivers, including the Ganges and the Yangtze, could shrink dramatically if emissions do not fall, hitting water supplies across a swathe of Asia.
- Thawing permafrost in places such as Alaska and Siberia could release vast quantities of greenhouse gases, potentially unleashing feedback loops driving faster warming.
Suggested Solutions
- A relatively straightforward solution to curbing biodiversity loss, especially in the face of climate change, is expanding the global network of large-scale protected areas on land and ocean.
- Protected areas have been implemented for years to conserve marine ecosystems.
- Studies continue to show that strict protected areas, which limit or prohibit human use, safeguard biodiversity while also enhancing resilience to environmental impacts, including climate change.
- But protected areas are not enough. The report also highlights an even more challenging component of the solution: Rapid reduction of greenhouse gas emissions must be achieved across institutional boundaries.
- The report calls for a five-fold increase in nationally determined contributions (NDCs), volunteered by countries under the 2015 Paris Agreement.
About Intergovernmental Panel on Climate Change (IPCC)
- The IPCC is the UN body for assessing the science related to climate change.
- It was established by the United Nations Environment Programme (UNEP) and the World Meteorological Organization (WMO) in 1988.
- It has 195 member states.
- The IPCC produces reports that support the UNFCCC.
- IPCC reports cover all relevant information to understand the risk of human-induced climate change, its potential impacts and options for adaptation and mitigation.
- The IPCC does not carry out its own original research.
- Thousands of scientists and other experts contribute on a voluntary basis.
IPCC Assessment Reports (AR)
- In accordance with its mandate, the IPCC prepares at regular intervals comprehensive Assessment Reports of scientific, technical and socio-economic information relevant for the understanding of human induced climate change, potential impacts of climate change and options for mitigation and adaptation.
Special Reports
- Special Reports have been prepared on topics such as aviation, regional impacts of climate change, technology transfer, emissions scenarios, land use, land use change and forestry, CO2 capture and storage and on the relationship between safeguarding the ozone layer and the global climate system.
Special Reports on Global Warming of 1.5 °C (SR1.5 – October 2018)
- SR1.5 said it was possible to keep the rise in temperature to within 1.5 °C, but for that the world would need to bring down its greenhouse gas emissions to half of its 2010 levels by 2030, and to net zero by 2050.
- Net-zero is achieved when the total emissions is balanced by the amount of absorption of CO2 through natural sinks, or removal of CO2 from the atmosphere through technological interventions.
- Some countries have already announced their intention to achieve the net zero target, but the most prominent emitters — China, US, India — have so far not done so.
Special Report on Climate Change and Land (SRCCL – August 2019)
- The land report said the various kinds of uses that land was being put to — forestry, agriculture, industries, urbanisation — had contributed about 5.2 billion tonnes of CO2 every year between 2007 and 2016.
- During the same time, trees and forests absorbed almost 11.2 billion tonnes of CO2 every year from the atmosphere.
- The sum total of these two processes meant that land, and the vegetation on it, was removing about 6 billion tonnes of CO2 from the atmosphere annually.
- It also pointed out that the global food system, which would include activities such as agriculture, cattle-rearing, food processing industry, energy consumed in these processes, and transportation of food items, could account for as much as a third of all greenhouse gases.
- It said nearly 25 per cent of all food produced globally was either lost or wasted.
- Seventy-seven countries announced efforts toward net-zero emissions by 2050.
The IPCC has three working groups
- The IPCC work is shared among three Working Groups, a Task Force and a Task Group.
- WG I aims at assessing the physical scientific basis of the climate system and climate change.
- WG II assesses the vulnerability of socio-economic and natural systems to climate change.
- WG III focuses on climate change mitigation, assessing methods for reducing GHG emissions, and removing greenhouse gases from the atmosphere.
- The IPCC is currently in its 6th Assessment Cycle, during which the IPCC will produce the Assessment reports of its three working groups, three special reports (SR1.5, SRCCL & SROCC), a refinement to the methodology report and the Synthesis report.
- The Synthesis Report will be the last of the AR6 products, due for release in 2022.
Marine Heat Waves (Hot Topic for UPSC Mains)
Similar Topic in Mains 2019: How do ocean currents and water masses differ in their impacts on marine life and the coastal environment? Give suitable examples? (Answer in 250 words)
- Marine heatwaves occur when ocean temperatures for a particular oceanic location are unusually extremely warm for an extended period and time of year.
- Marine heatwaves can occur in summer or winter and have a significant impact on marine ecosystems and world weather patterns.
Image Credits: Marineheatwaves.org
IPCC SROCC on marine heat waves
- Marine heat waves have become twice more frequent in the past four decades and are lasting longer.
- The report finds that human activities are responsible for 84 to 90 per cent of the marine heat waves that occurred in the last one decade
- By 2081, the frequency of marine heat waves could jump by 20 to 50 times.
Impact on marine productivity
- Marine heat waves have resulted in large-scale coral bleaching, which takes more than 15 years for corals to recover from.
- Marine heat waves reduce mixing between water layers and, as a consequence, the supply of oxygen and nutrients for marine life.
- Pacific Ocean had seen such unusually warm water, it had boosted the growth of toxin-producing algae and suppressed the growth of small organisms at the base of the ocean food chain.
Impact on weather patterns
- The direct cause of marine heat waves is weak winds.
- A more pronounced effect of marine heat waves would be on global wind circulation and ocean currents.
- IPCC report indicates, the Atlantic Meridional Overturning Circulation (AMOC), which ensures northward flow of warm, salty water in the upper layers of the Atlantic and a southward flow of colder, deep waters, has already weakened.
- Any substantial weakening of the AMOC would cause
- further decrease in marine productivity in the North Atlantic,
- more storms in Northern Europe,
- less Sahelian summer rainfall and South Asian summer rainfall,
- a reduced number of tropical cyclones in the Atlantic and
- an increase in regional sea level along the northeast coast of North America, the report warns.
More severe cyclonic storms
- SROCCC says there is an emerging evidence of an annual increase in percentage of category 4 and 5 storms.
- These storms further sustain their strength by feeding on the moisture over warm ocean waters.
- Slow wind speed was a reason behind intensification of extremely severe cyclone Fani, of category 4, which battered the eastern Indian coast in May this year.
IPCC’s take on Sea Level Rise and Coastal Flooding
- In the absence of an El Niño event, the World Meteorological Organization (WMO) has already hinted at global warming as a cause of current increase in sea surface temperatures around the world.
- However, the report warns, sea level rise could reach 60 to 110 cm if emissions continue to increase strongly.
Extreme floods to increase economic loss 166 times in coastal megacities: IPCC
- Economic losses due to extreme flooding will soar 166 times more by 2050, unless world’s coastal megacities adapt to a climate change, warned a recent report by IPCC.
- India’s financial capital, Mumbai, will also be among those bearing the brunt.
- More than half the global population live in cities, most of which are located in low-lying islands and coasts.
A similar study says
- The no of people in India threatened by rising sea-levels is at least 7 times more than previously estimated.
- It says 36 million people along the Indian coastlines currently live on land that will fall below the annual flood level by 2050, exposing them to risks of flooding.
- The previous estimate was of five million people in these areas being exposed to these risks.
- The study found that 300 million people, and not 80 million as estimated earlier, across the globe were currently living in areas that were below the annual coastal flood line.
- Almost 80 per cent of these 300 million people live in China, Bangladesh, India, Vietnam, Indonesia and Thailand. China alone accounted for 43 million.
- In each of several dozen major cities — including Bangkok, Hong Kong, Shanghai, Taizhou, Surabaya, Dhaka, Mumbai, Ho Chi Minh City and Osaka — millions will find themselves in flood zones.
Vulnerable areas in India
- Bhuj, Jamnagar, Porbandar, Surat, Bharuch and Mumbai are much more susceptible to rising sea levels than earlier assessments.
- On the eastern side, almost the entire coastline of West Bengal and Odisha have been found under threat.
- Except for some areas near Kakinada, the threats to the coastlines of the southern states have not been affected by the new measurements.
Why so many IPCC reports now?
- Last year’s IPCC report on 1.5°C mentioned that humanity had barely 12 years to keep alive the hopes of restricting global temperature rise to within 1.5°C from pre-industrial times.
- Next year, 2020, happens to be the transition year for the international climate regime, from the Kyoto Protocol to the Paris Agreement.
- The Kyoto regime has been a major underachiever in reducing greenhouse gas emissions.
- The Paris Agreement, in so far as it makes it mandatory for every country to initiate actions and not just rich and developed nations as under the Kyoto Protocol, is expected to deliver much better results.
- As required by the Paris Agreement, every country had already finalised and submitted a climate action plan, called Nationally Determined Contributions, or NDCs, in 2015.
- The NDCs currently submitted have targets or action plans for 2025 or 2030.
- The assessment of several NDCs has concluded that these actions were not adequate to achieve the global goal of keeping temperature rise within 2 °C from pre-industrial times.
- But the NDCs have to be updated every five years, and the countries are scheduled to do it next year.
- The Paris Agreement also provides for a review of all climate actions in 2023 to assess whether the individual actions of countries were adding up to what was required to achieve the goal.
- The move to get countries to commit to a net-zero target by 2050 is a part of these efforts.
Last updated on December 12, 2024 7:17 PM