UN climate report warns oceans rising, ongoing warming
by Intergovernmental Panel on Climate Change (IPCC)
6:24pm 22nd Sep, 2019
UN climate report warns oceans rising, ongoing warming, by IPCC, UN News, agencies
The latest Intergovernmental Panel on Climate Change (IPCC) Special Report highlights the urgency of prioritizing timely, ambitious and coordinated action to address unprecedented and enduring changes in the ocean and cryosphere.
The report reveals the benefits of ambitious and effective adaptation for sustainable development and, conversely, the escalating costs and risks of delayed action.
The ocean and the cryosphere - the frozen parts of the planet - play a critical role for life on Earth. A total of 670 million people in high mountain regions and 680 million people in low-lying coastal zones depend directly on these systems. Four million people live permanently in the Arctic region, and small island developing states are home to 65 million people.
Global warming has already reached 1C above the pre-industrial level, due to past and current greenhouse gas emissions. There is overwhelming evidence that this is resulting in profound consequences for ecosystems and people. The ocean is warmer, more acidic and less productive. Melting glaciers and ice sheets are causing sea level rise, and coastal extreme events are becoming more severe.
The IPCC Special Report on the Ocean and Cryosphere in a Changing Climate, approved on 24 September 2019 by the 195 IPCC member governments, provides new evidence for the benefits of limiting global warming to the lowest possible level - in line with the goal that governments set themselves in the 2015 Paris Agreement. Urgently reducing greenhouse gas emissions limits the scale of ocean and cryosphere changes. Ecosystems and the livelihoods that depend on them can be preserved.
'The open sea, the Arctic, the Antarctic and the high mountains may seem far away to many people', said Hoesung Lee, Chair of the IPCC. 'But we depend on them and are influenced by them directly and indirectly in many ways - for weather and climate, for food and water, for energy, trade, transport, recreation and tourism, for health and wellbeing, for culture and identity'.
'If we reduce emissions sharply, consequences for people and their livelihoods will still be challenging, but potentially more manageable for those who are most vulnerable', Lee said. 'We increase our ability to build resilience and there will be more benefits for sustainable development'.
Knowledge assessed in the report outlines climate-related risks and challenges that people around the world are exposed to today and that future generations will face. It presents options to adapt to changes that can no longer be avoided, manage related risks and build resilience for a sustainable future. The assessment shows that adaptation depends on the capacity of individuals and communities and the resources available to them.
More than 100 authors from 36 countries assessed the latest scientific literature related to the ocean and cryosphere in a changing climate for the report, referencing about 7,000 scientific publications.
The IPCC Special Report is a key scientific input for world leaders gathering in forthcoming climate and environment negotiations, such as the UN Framework Convention on Climate Change Conference (COP25) in Chile in December.
'The world's ocean and cryosphere have been 'taking the heat' from climate change for decades, and consequences for nature and humanity are sweeping and severe', said Ko Barrett, Vice-Chair of the IPCC. 'The rapid changes to the ocean and the frozen parts of our planet are forcing people from coastal cities to remote Arctic communities to fundamentally alter their ways of life', she added.
'By understanding the causes of these changes and the resulting impacts, and by evaluating options that are available, we can strengthen our ability to adapt', she said. 'The Special Report on the Ocean and Cryosphere in a Changing Climate provides the knowledge that facilitates these kinds of decisions'.
Major changes in high mountains affecting downstream communities
People in mountain regions are increasingly exposed to hazards and changes in water availability, the report said.
Glaciers, snow, ice and permafrost are declining and will continue to do so. This is projected to increase hazards for people, for example through landslides, avalanches, rockfalls and floods.
Smaller glaciers found for example in Europe, eastern Africa, the tropical Andes and Indonesia are projected to lose more than 80% of their current ice mass by 2100 under high emission scenarios. The retreat of the high mountain cryosphere will continue to adversely affect recreational activities, tourism, and cultural assets.
As mountain glaciers retreat, they are also altering water availability and quality downstream, with implications for many sectors such as agriculture and hydropower.
'Changes in water availability will not just affect people in these high mountain regions, but also communities much further downstream', said Panmao Zhai, Co-Chair of IPCC Working Group I.
'Limiting warming would help them adapt to changes in water supplies in mountain regions and beyond, and limit risks related to mountain hazards', he said. 'Integrated water management and transboundary cooperation provides opportunities to address impacts of these changes in water resources'.
Melting ice, rising seas
Glaciers and ice sheets in polar and mountain regions are losing mass, contributing to an increasing rate of sea level rise, together with expansion of the warmer ocean.
While sea level has risen globally by around 15 cm during the 20th century, it is currently rising more than twice as fast - 3.6 mm per year - and accelerating, the report showed.
Sea level will continue to rise for centuries. It could reach around 30-60 cm by 2100 even if greenhouse gas emissions are sharply reduced and global warming is limited to well below 2C, but around 60-110 cm if greenhouse gas emissions continue to increase strongly.
'In recent decades the rate of sea level rise has accelerated, due to growing water inputs from ice sheets in Greenland and Antarctica, in addition to the contribution of meltwater from glaciers and the expansion of warmer sea waters', said Valarie Masson-Delmotte, Co-Chair of IPCC Working Group I.
'This new assessment has also revised upwards the projected contribution of the Antarctic ice sheet to sea level rise by 2100 in the case of high emissions of greenhouse gases', she said. 'The wide range of sea level projections for 2100 and beyond is related to how ice sheets will react to warming, especially in Antarctica, with major uncertainties still remaining'.
More frequent extreme sea level events
Sea level rise will increase the frequency of extreme sea level events, which occur for example during high tides and intense storms. Indications are that with any degree of additional warming, events that occurred once per century in the past will occur every year by mid-century in many regions, increasing risks for many low-lying coastal cities and small islands.
Without major investments in adaptation, they would be exposed to escalating flood risks, the report shows. Some island nations are likely to become uninhabitable due to climate-related ocean and cryosphere change, the report said, but habitability thresholds remain extremely difficult to assess.
Increases in tropical cyclone winds and rainfall are exacerbating extreme sea level events and coastal hazards. Hazards will be further be intensified by an increase in the average intensity, magnitude of storm surge and precipitation rates of tropical cyclones, especially if greenhouse gas emissions remain high.
'Various adaptation approaches are already being implemented, often in response to flooding events, and the report highlights the diversity of options available for each context to develop integrated responses anticipating the full scale of future sea level rise', said Masson-Delmotte.
Changing ocean ecosystems
Warming and changes in ocean chemistry are already disrupting species throughout the ocean food web, with impacts on marine ecosystems and people that depend on them, the report said.
To date, the ocean has taken up more than 90% of the excess heat in the climate system. By 2100, the ocean will take up 2 to 4 times more heat than between 1970 and the present if global warming is limited to 2C, and up to 5 to 7 times more at higher emissions. Ocean warming reduces mixing between water layers and, as a consequence, the supply of oxygen and nutrients for marine life.
Marine heatwaves have doubled in frequency since 1982 and are increasing in intensity. They are projected to further increase in frequency, duration, extent and intensity. Their frequency will be 20 times higher at 2C warming, compared to pre-industrial levels. They would occur 50 times more often if emissions continue to increase strongly.
The ocean has taken up between 20 to 30% of human-induced carbon dioxide emissions since the 1980s, causing ocean acidification. Continued carbon uptake by the ocean by 2100 will exacerbate ocean acidification.
Ocean warming and acidification, loss of oxygen and changes in nutrient supplies, are already affecting the distribution and abundance of marine life in coastal areas, in the open ocean and at the sea floor.
Shifts in the distribution of fish populations have reduced the global catch potential. In the future, some regions, notably tropical oceans, will see further decreases, but there will be increases in others, such as the Arctic. Communities that depend highly on seafood may face risks to nutritional health and food security.
'Cutting greenhouse gas emissions will limit impacts on ocean ecosystems that provide us with food, support our health and shape our cultures', said the Co-Chair of IPCC Working Group II. 'Reducing other pressures such as pollution will further help marine life deal with changes in their environment, while enabling a more resilient ocean'.
Policy frameworks, for example for fisheries management and marine-protected areas, offer opportunities for communities to adapt to changes and minimize risks for our livelihoods, he added.
Declining Arctic sea ice, thawing permafrost
The extent of Arctic sea ice is declining in every month of the year, and it is getting thinner. If global warming is stabilized at 1.5C above pre-industrial levels, the Arctic ocean would only be ice-free in September, the month with the least ice - once in every hundred years. For global warming of 2C, this would occur up to one year in three.
Some people living in the Arctic, especially indigenous peoples, have already adjusted their traveling and hunting activities to the seasonality and safety of land, ice and snow conditions, and some coastal communities have planned for relocation. Their success in adapting depends on funding, capacities, and institutional support, the report shows.
Permafrost ground that has been frozen for many years is warming and thawing and widespread permafrost thaw is projected to occur in the 21st century. Even if global warming is limited to well below 2C, around 25% of the near-surface (3-4 meter depth) permafrost will thaw by 2100. If greenhouse gas emissions continue to increase strongly, there is a potential that around 70% near-surface permafrost could be lost.
Arctic and boreal permafrost hold large amounts of organic carbon, almost twice the carbon in the atmosphere, and have the potential to significantly increase the concentration of greenhouse gases in the atmosphere if they thaw. It is unclear whether there is already a net release of carbon dioxide or methane due to the ongoing thaw of the Arctic permafrost.
In the future, increased plant growth can increase the storage of carbon in soils and offset carbon release from permafrost thaw, but not at the scale of large changes on the long term.
Wildfires are disturbing ecosystems in most tundra and boreal as well as mountain regions.
Knowledge for urgent action
The report finds that strongly reducing greenhouse gas emissions, protecting and restoring ecosystems, and carefully managing the use of natural resources would make it possible to preserve the ocean and cryosphere as a source of opportunities that support adaptation to future changes, limit risks to livelihoods and offer multiple additional societal benefits.
'We will only be able to keep global warming to well below 2C above pre-industrial levels if we effect unprecedented transitions in all aspects of society, including energy, land and ecosystems, urban and infrastructure as well as industry.
The ambitious climate policies and emissions reductions required to deliver the Paris Agreement will also protect the ocean and cryosphere and ultimately sustain all life on Earth, said Debra Roberts, Co-Chair of IPCC Working Group II.
SROCC provides the best available scientific knowledge to empower governments and communities to take action, embedding that scientific knowledge on unavoidable change and plausible futures into their own context, to limit the scale of risks and climate impacts.
The report gives evidence of the benefits of combining scientific with local and indigenous knowledge to develop suitable options to manage climate change risks and enhance resilience. This is the first IPCC report that highlights the importance of education to enhance climate change, ocean and cryosphere literacy.
The more decisively and the earlier we act, the more able we will be to address unavoidable changes, manage risks, improve our lives and achieve sustainability for ecosystems and people around the world today and in the future, Roberts said.
Climate crisis reducing land's ability to sustain humanity, says IPCC - ecosystems never before under such threat and restoration is urgent. (IPCC, agencies)
The climate crisis is damaging the ability of the land to sustain humanity, with cascading risks becoming increasingly severe as global temperatures rise, according to a landmark UN report compiled by some of the world's top scientists.
Global heating is increasing droughts, soil erosion and wildfires while diminishing crop yields in the tropics and thawing permafrost near the poles, says the report by the Intergovernmental Panel on Climate Change.
Further heating will lead to unprecedented climate conditions at lower latitudes, with potential growth in hunger, migration and conflict and increased damage to the great northern forests.
The report, approved by the world's governments, makes clear that humanity faces a stark choice between a vicious or virtuous circle. Continued destruction of forests and huge emissions from cattle and other intensive farming practices will intensify the climate crisis, making the impacts on land still worse.
However, action now to allow soils and forests to regenerate and store carbon, and to cut meat consumption by people and food waste, could play a big role in tackling the climate crisis, the report says.
Such moves would also improve human health, reduce poverty and tackle the huge losses of wildlife across the globe, the IPCC says.
Burning of fossil fuels should end to avoid 'irreversible loss in land ecosystem services required for food, health and habitable settlements', the report says.
'This is a perfect storm', said Dave Reay, a professor at the University of Edinburgh who was an expert reviewer for the IPCC report. 'Limited land, an expanding human population, and all wrapped in a suffocating blanket of climate emergency. Earth has never felt smaller, its natural ecosystems never under such direct threat'.
Professor Jim Skea, from the IPPC, said the land was already struggling and climate change was adding to its burdens. Almost three-quarters of ice-free land was now directly affected by human activity, the report says.
Poor land use is also behind a quarter of the planet's greenhouse gas emissions - the destruction of forests, huge cattle herds and overuse of chemical fertilisers being key factors.
Emissions relating to fertilisers have risen ninefold since the early 1960s. Rising temperatures are causing deserts to spread, particularly in Asia and Africa impacting over 500 million people the report says.
One stark conclusion in the IPCC report is that soil, upon which humanity is entirely dependent, is being lost more than 100 times faster than it is being formed in ploughed areas; and lost up to 20 times faster even on fields that are not tilled.
* IPCC report on Climate Change and Land: http://bit.ly/2YQ0MG9
* IPCC World must not exceed 1.5C Summary (34pp): http://bit.ly/2y7hz9b
According to new data from the World Meteorological Organization and Copernicus Climate Change Programme, July at least equalled, if not surpassed, the hottest month in recorded history. This follows the warmest ever June on record.
The data from the Copernicus Climate Change Programme, run by the European Centre for Medium-Range Weather Forecasts, is fed into the UN system by WMO. The figures show that, based on the first 29 days of the month, July 2019 will be on par with, and possibly marginally warmer than the previous warmest July, in 2016, which was also the warmest month ever.
The latest figures are particularly significant because July 2016 was during one of the strongest occurrence of the El Nino phenomenon, which contributes to heightened global temperatures. Unlike 2016, 2019 has not been marked by a strong El Nino.
'We have always lived through hot summers. But this is not the summer of our youth. This is not your grandfather's summer', said UN Secretary-General Antonio Guterres, announcing the data in New York.
July 2019 will be around 1.2C warmer than the pre-industrial era, according to the data.
'All of this means that we are on track for the period from 2015 to 2019 to be the five hottest years on record. This year alone, we have seen temperature records shattered from New Delhi to Anchorage, from Paris to Santiago, from Adelaide and to the Arctic Circle. If we do not take action on climate change now, these extreme weather events are just the tip of the iceberg. And, indeed, the iceberg is also rapidly melting', Mr Guterres said.
Preventing irreversible climate disruption is the race of our lives, and for our lives. It is a race that we can and must win, he underlined.
Exceptional heat has been observed across the globe in recent week, with a string of European countries logging record highs temperatures that have caused disruption to transport and infrastructure and stress on people's health and the environment. As the heat dome spread northwards through Scandinavia and towards Greenland, it accelerated the already above average rate of ice melt.
July has re-written climate history, with dozens of new temperature records at local, national and global level, said WMO Secretary-General Petteri Taalas.
The extraordinary heat was accompanied by dramatic ice melt in Greenland, in the Arctic and on European glaciers. Unprecedented wildfires raged in the Arctic for the second consecutive month, devastating once pristine forests which used to absorb carbon dioxide and instead turning them into fiery sources of greenhouse gases. This is not science fiction. It is the reality of climate change. It is happening now and it will worsen in the future without urgent climate action, Mr Taalas said.
WMO expects that 2019 will be in the five top warmest years on record, and that 2015-2019 will be the warmest of any equivalent five-year period on record. Time is running out to reign in dangerous temperature increases with multiple impacts on our planet, he said.
Such heatwaves are consistent with what we expect from climate change and rising global temperatures.
Belgium, Germany, Luxembourg, the Netherlands and the United Kingdom saw new national temperature records on 25 July, as weather maps were redrawn to include - for the first time - temperatures of above 40C. Paris recorded its hottest day on record, with a temperature of 42.6C at 16:32, an unprecedented value since the beginning of measurements.
The heatwave was caused by warm air coming up from North Africa and Spain and this was then transported from Central Europe to Scandinavia, Norway saw new station records on 27 July, and 28 locations had tropical nights above 20C. The Finnish capital Helsinki set a new station record of 33.2C on 28 July and in the south of Finland, Porvoo saw a temperature of 33.7C.
The anomalously high temperatures are expected to enhance melting of the Greenland ice sheet, which already saw an extensive melt episode between 11 and 20 June. The persistent high melt and runoff in the last few weeks means the season total is running near tothe 2012 record high loss, according to Polar climate scientists monitoring the Greenland ice sheet.
The station Nord, situated 900 kilometres from the North Pole, measured a temperature of 16C and in western Greenland, the station of Qaarsut (near 71N) recorded a temperature of 20.6C on 30 July. At Summit Camp station, at the peak of the ice sheet and at an altitude of 3200m, a temperature of 0.0C was measured.
It is important to remember that that any given day or year, Greenland ice sheet surface mass budget is a result largely of weather, though with the background climate trend affecting this, tweeted Ruth Mottram, a climate scientist with the Danish Meteorological Institute.
This will also impact Arctic sea ice, which where the loss of ice extent through the first half of July matched loss rates observed in 2012, the year which had the lowest September sea ice extent in the satellite record, according to the US National Snow and Ice Data Center.
The high temperatures also fanned wildfire activity in the Arctic, including in Greenland, Alaska and Siberia.
The Russian Federal Forestry Agency estimates that, as of 29 July, wildfires in Siberia have burned 33,200 square kilometres, with 745 active fires, causing massive ecological devastation and impacting air quality for hundreds of kilometres. The smoke can be clearly seen from space.
The European Centre for Medium-Range Weather Forecasts/Copernicus Atmosphere Monitoring Service estimated that July 2019 wildfire CO2 emissions for the Arctic Circle totalled 75.5047 megatonnes, which is comparable to the 2017 annual fossil fuel emissions of Colombia. This was more than double July 2018 levels, and followed a record month in June.
By burning vegetation, the fires also reduce the capacity of the biosphere to absorb carbon dioxide. Action against climate change necessitates rather that we should expand this capacity, said Oksana Tarasova, Chief of WMO's Atmosphere and Environment Research Division.
The July heatwave follows an unusually early and exceptionally intense heatwave in June, which set new temperature records in Europe and ensured that the month of June was the hottest on record for the continent, with the average temperature of 2C above normal.
June was also the warmest June on record globally.
In parts of Europe, the heat was accompanied by below-average precipitation. On 31 July, WMO's regional climate monitoring centre for Europe, operated by the German Weather Service, or Deutscher Wetterdienst, updated its Climate Watch advisory on drought. This provides guidance to national meteorological and hydrological services in issuing climate advisories for their territory.
A continuation of drought conditions and below-normal precipitation in large parts of Central and Northeastern Europe. In these areas mostly only 60-80 % of normal precipitation was recorded in June, in some parts even less.
There was also only scarce rainfall in July and forecasts show continued below-normal precipitation in most of the area with weekly deficits of partly 10-30mm for this week with a probability of 80% and higher, it said.
In the wake of the heatwave, some European countries have faced very heavy precipitation, but it is not enough to undo the impact of drought conditions.
Next week, above-normal precipitation will be expected over Central Europe, but this might not be sufficient to compensate for the rain deficits during the weeks before and therefore soils will be still dry. Northeastern Europe (Baltic countries and southern Finland) will still receive not more than below-normal to normal precipitation next week and therefore drought conditions are likely to continue.
Drought conditions can result in harvest losses, forest fires, lack of animal food water restrictions, restrictions of ship traffic due to low water levels, said the Deutscher Wetterdienst.
During the heatwave, national meteorological and hydrological services issued heat alerts - including the top-level red alert - and, in some areas, fire warnings to minimize the risk to life and the environment. Heat-health action plans mobilized civil protection efforts across the region.
Heat events kill thousands of people every year and often trigger secondary events such as wildfires and failures to electrical grids. Urbanization compounds the problem. Heat stroke, dehydration, cardiovascular and other temperature related diseases are major health risks.
The new absolute record of 42.6C for Paris was recorded on 25 July at the centennial weather station in Paris-Montsouris, and broke the previous record dating back to 28 July 1947 with 40.4C. This temperature is typical of the average July temperature in Bagdad, Iraq. The night of 24/25 July was also exceptionally hot, with minimal temperatures above 25C and even 28.3C in a downtown Paris weather station. What is striking is the margin with which the records were beaten. Lille recorded 41.4C, that's nearly 4C above the previous record. France set a new national temperature record of 46C during the last heatwave on 28 June.
The Deutscher Wetterdienst described 25 July as a day which will make weather history. Germany set a new national temperature record (provisional figure) of 42.6C in Lingen, near the Dutch border, defeating the old record by 2.3C. There were 25 weather stations above 40C. The previous national temperature record was 40.3C (5 July 2015).
The Netherlands broke a 75-year-old heat record (set in Aug 1944) with a temperature of 40.7C at Gilye Rijen. Belgium also set a new national record of 41.8C. Luxembourg set a new national record of 40.8C.
On 25 July, temperatures in the United Kingdom reached 38.7C at Cambridge Botanical Gardens, the highest ever officially recorded, breaking the previous record of 38.5C recorded in Faversham, Kent, in August 2003, according to the Met Office.
Climate change and heatwaves
Such intense and widespread heatwaves carry the signature of man-made climate change. This is consistent with the scientific finding showing evidence of more frequent, drawn out and intense heat events as greenhouse gas concentrations lead to a rise in global temperatures, according to Johannes Cullmann, Director of WMO's Climate and Water Department. WMO will submit a five year report on the state of the climate 2015-2019 to the UN Climate Action Summit in September.
Many scientific studies have been conducted on the links between climate change and heatwaves.
Human-influenced climate change is likely to have added 1.5-3C to the extreme temperatures recorded during Europe's July 2019, according to a report by World Weather Attribution, which underlined the manifold risks.
Heatwaves the height of summer pose a substantial risk to human health and are potentially lethal. This risk is aggravated by climate change, but also by other factors such as an aging population, urbanisation, changing social structures, and levels of preparedness. The full impact is only known after a few weeks when the mortality figures have been analysed.
Effective heat emergency plans, together with accurate weather forecasts such as those issued before this heatwave, reduce impacts and are becoming even more important in light of the rising risks, it said.
It is noteworthy that every heatwave analysed so far in Europe in recent years (2003, 2010, 2015, 2017, 2018, June 2019, this study) was found to be made much more likely and more intense due to human-induced climate change. How much more depends very strongly on the event definition: location, season, intensity and duration. The July 2019 heatwave was so extreme over continental Western Europe that the observed magnitudes would have been extremely unlikely without climate change, it added.
In its In its Fifth Assessment Report, released in 2014, the Intergovernmental Panel on Climate Change said that 'it is very likely that human influence has contributed to the observed global scale changes in the frequency and intensity of daily temperature extremes since the mid-20th century. It is likely that human influence has more than doubled the probability of occurrence of heat waves in some locations'.
In its 2018 report on Global Warming of 1.5C, the IPCC said that climate-related risks to health, livelihoods, food security, water supply, human security, and economic growth are projected to increase with global warming of 1.5C and increase further with 2C.
Limiting warming to 1.5C rather than 2C could result in 420 million fewer people being exposed to severe heatwaves, it said.
Between 2000 and 2016, the number of people exposed to heatwaves was estimated to have increased by around 125 million persons, as the average length of individual heatwaves was 0.37 days longer, compared to the period between 1986 and 2008, according to the World Health Organization.
Many countries have issued national climate assessments and scenarios which underline the close connection between climate change and heat.
For instance, the UK State of the Climate report showed an increase in higher maximum temperatures and longer warm spells. The hottest day of the year for the most recent decade (2008-2017) has increased by 0.8C above the 1961-1990 average. Warm spells have also more than doubled in length - increasing from 5.3 days in 1961-90 to over 13 days in the most recent decade (2008-2017).
The summer of 2018 was the joint warmest on record for the UK as a whole and the hottest ever for England. The Met Office research showed that human-induced climate change made the 2018 record-breaking UK summer temperatures about 30 times more likely than it would have been naturally. By 2050 these are expected to happen every other year.
France has also reported an increase in the frequency and intensity of heatwaves over the past 30 years,.
The increases in the highest temperatures are even more pronounced than for the average seasonal temperatures. By 2060, the hottest days in an average summer could be up to 5.5C higher than they are today. This is explained in part by the fact that less water will be evaporating and cooling the ground because there will be less moisture in the soil, says the Swiss report.
The regions of Europe that surround the Mediterranean Sea, including Switzerland, are affected by some of the most severe increases in temperature extremes worldwide. This trend has been apparent even over recent decades and is very likely to continue into the future, it says.
http://public.wmo.int/en/media/news/july-equalled-and-maybe-surpassed-hottest-month-recorded-history http://climatecentre.org/news/1177/wmo-says-july-a-rewrote-climate-historya http://www.un.org/en/climatechange/
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