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“Such high-risk changes are considered unlikely in this century, but are by definition hard to predict.”, The WMO 2019 United in Science report said: “With continued warming, systems can reach tipping points where they rapidly collapse or a major, largely unstoppable transformation is initiated. As another example, Arctic warming could destabilise methane (a greenhouse gas) trapped in ocean sediments and permafrost, potentially leading to a rapid release of a large amount of methane. If such a rapid release occurred, then major, fast climate changes would ensue. This perspective is important as a reminder that only a very small change to natural processes is required to compensate for (or exacerbate) anthropogenic emissions. Although we currently lack the large Northern Hemisphere ice sheets of the Pleistocene, there are of course still large ice sheets on Greenland and Antarctica. We are currently living through one of these interglacial periods. * About 36.6 billion tonnes (9.98 GtC) from fossil fuels and cement production in 2018, plus about 5.5 Gt from land use change and deforestation (WMO Greenhouse Gas Bulletin #15). In 2018 this reached 496 ppm according to the US National Oceanic and Atmospheric Administration (NOAA) Annual Greenhouse Gas Index (AGGI). Global air temperatures do appear to have risen about 0.6 °C over the last century, though this has been irregular rather than steady, and does not correlate well with the steady increase in greenhouse gas – notably CO2 – concentrations. The climate of the Earth has always changed, but the study of palaeoclimatology or "past climates" shows us that the… It is based at the WMO in Geneva. The third part identifies options for mitigation of climate change. T he work of the Intergovernmental Panel on Climate Change (IPCC) represents the consensus of the international scientific community on climate change science. The present warm period (known as the Holocene) became established only 11,500 years ago, since when our climate has been relatively stable. National and international science academies and scientific societies have assessed current scientific opinion on global warming.These assessments are generally consistent with the conclusions of the Intergovernmental Panel on Climate Change.. The focus of attention regarding global warming has been the atmosphere, where the heat is initially retained. Climate change is any long-term alteration in average weather patterns, either globally or regionally. The greenhouse effect itself occurs when short-wave solar radiation (which is not impeded by the greenhouse gases) heats the surface of the Earth, and the energy is radiated back through the Earth's atmosphere as heat, with a longer wavelength. A large part of the increase in all greenhouse gases is attributed to human sources, i.e. Carbon isotopic data show that this warming event (called by some the Paleocene-Eocene Thermal Maximum, or PETM) was accompanied by a major release of 1500-2000 billion tonnes or more of carbon (5550-7400 billion tonnes or more of CO2) into the ocean and atmosphere. Registered office: Tower House, 10 Southampton Street, London, WC2E 7HA, United Kingdom, Reuse of World Nuclear Association Content, Intergovernmental Panel on Climate Change, Climate change: evidence from the geological record, Anthropogenic sulfur dioxide emissions: 1850-2005, Climate Change: evidence from the geological record, An Addendum to the Statement on Climate Change: Evidence from the Geological Record, CO2 Implications of Electricity Generation. Clearly, any country excluding or phasing out nuclear energy is raising the overall cost of meeting emission reduction targets. Certain inputs to the atmosphere can be discerned and readily quantified – carbon dioxide from fossil fuel burning* and CFCs from refrigerants for instance. Climate change has inexorably stacked the deck in favor of bigger and more intense fires across the American West over the past few decades, science … Some scientific bodies have recommended specific policies to governments, and science can play a role in informing an effective response to climate change. Then there is the question of residence time in the atmosphere. Cold days, cold nights and frost have become less frequent, while hot days, hot nights, and heat waves have become more frequent. Nuclear power plants do not emit these gases. The average global temperature for 2015-2019 is on track to be the warmest of any equivalent period on record. Studies of the Last Glacial Maximum (about 20,000 years ago) suggest that the climate sensitivity, based on rapidly-acting factors like snow melt, ice melt and the behaviour of clouds and water vapour, lies in the range 1.5-6.4 °C. It has increased by one-third in the last 200 years, and half of that in the last 30 years. * Part of this 'window' (12.5-18 µm) is largely blocked by carbon dioxide absorption, even at the low levels originally existing in the atmosphere. Our climate scientists have been working with the UK government and other research agencies on a programme called The AVOID2 programme on avoiding 'dangerous' climate change, which explores the potential long-term effects of 'dangerous' climate change. In the major El Niño-Southern Oscillation event in 1997-98 the globally-averaged air temperature reached its highest level in the 20th century as the ocean lost heat to the atmosphere, mainly by evaporation, with a major effect on regional rainfall. In respect to enhancing the greenhouse effect, or the likelihood of AGW, the particular issue is focused in the 8-18 µm band where water vapour is a weak absorber of radiation and where the Earth's thermal radiation is greatest. Average life-cycle carbon dioxide-equivalent emissions for different electricity generators (Source: IPCC). The ocean absorbs nearly 25% of the annual emissions of anthropogenic CO, Implementing current unconditional nationally-determined contributions (NDC) to reducing CO. A Synthesis Report, including a Summary for Policymakers, is also published for all three reports. Multiple lines of evidence support very substantial Arctic warming since the mid-20th century, and anthropogenic influences have very likely contributed to Arctic sea ice loss since 1979. The first details the physical scientific basis for climate change. Relating these atmospheric concentrations to emissions, sources and sinks is a steadily evolving sphere of scientific inquiry. It does not conduct any research nor does it monitor climate-related data or parameters. Over the past 2.6 million years (the Pleistocene and Holocene), the Earth’s climate has been on average cooler than today, and often much colder. More bonds = more vibrations = more IR absorption. The science behind the politics of climate change took a step forward and also ratcheted up concerns with the release of the Third Assessment Report from the UN's Intergovernmental Panel on Climate Change (IPCC), in 2001. Of this 545 GtC, about 240 GtC (44%) had accumulated in the atmosphere, 155 GtC (28%) had been taken up in the oceans with slight consequent acidification, and 150 GtC (28%) had accumulated in the terrestrial ecosystems. The greenhouse effect occurs naturally, providing a habitable climate. Concentrations of some of them have increased steadily during the 20th century and into the 21st, with carbon dioxide (CO2) rising from under 300 parts per million (ppm) to over 400 ppm. The first two of four headline statements from Climate Change 2014: Synthesis Report (the Synthesis Report of the Fifth Assessment Report) are: Among the Fifth Assessment Report findings on physical science were: In the Fifth Assessment Report, four scenarios for future carbon emissions to 2100 ranged from means of 270 GtC, assuming substantial cuts in emissions and correlated with best-case radiative forcing of 2.5 W/m2, to 1685 GtC correlated with 8.5 W/m2 radiative forcing. Coal burning was responsible for 52% of the fossil fuel emissions growth in 2010 (gas 23% and liquid 18%). CO2 levels were already high at the time. More than 60% of the net energy increase in the climate system was stored in the upper ocean (0-700 m) from 1971 to 2010, and about 30% is stored in the ocean below 700 m. Anthropogenic influences likely contributed to the retreat of glaciers since the 1960s and to the diminution of the Greenland ice sheet since 1993. It is very likely that there is a substantial anthropogenic contribution to the global mean sea level rise since the 1970s. In 2016 the Aliso Canyon underground gas storage in California was shut down after a massive leak of almost 100,000 tonnes of methane and over 7000 tonnes of ethane. 1 This would represent more than a doubling of the current nuclear output by 2030. Geologists have recently contributed to improved estimates of climate sensitivity (defined as the increase in global mean temperature resulting from a doubling in atmospheric CO2 levels). It is currently estimated to be 1.1 °C (±0.1 °C) above pre-industrial (1850-1900) times. The models are constantly being refined, and in 2013 the IPCC noted “differences between simulated and observed trends over periods as short as 10 to 15 years (e.g. In addition to these well-documented radiative gases there is increasing concern about sulfur hexafluoride (SF6) used in grid switchgear, with about 8000 tonnes emitted annually and increased use envisaged. That period is known as the ‘Ice Age’, a series of glacial episodes separated by short warm ‘interglacial’ periods that lasted between 10,000-30,000 years. These reproduce observed continental-scale surface temperature patterns and trends over many decades, including the more rapid warming since the mid-20th century and the cooling immediately following large volcanic eruptions, thus giving a range and probability of climatic impacts on different regions of the world. Ocean acidification – a decrease of about 0.03 in pH since 1990 – is an issue, possibly affecting organisms which rely on calcium carbonate. There are clear benefits to keeping warming to 1.5 °C compared with 2 °C or higher. The Sixth Assessment Report is anticipated in 2021, but meanwhile there are two other relevant reports (see below). The September minimum extent has decreased, and the winter thickness is less. However, there is doubt about whether in practice this occurs to the extent previously thought. Master the basics of climate science so you can better understand the news, evaluate scientific evidence, and explain global warming to anyone. Global Carbon Project, Global Carbon Budget Climate scientists use a concept called radiative forcing to quantify the effect of these increased concentrations on climate. “A well-known example is the south-north ocean overturning circulation, which is maintained by cold salty water sinking in the North Atlantic and which involves the transport of extra heat to the North Atlantic via the Gulf Stream. This is based on the high confidence in an anthropogenic influence on the two largest contributions to sea level rise – thermal expansion and glacier mass loss. The first part of each Assessment Report on the physical science basis of climate change (from Working Group I) concluded that the evidence that human-derived greenhouse gas emissions had already had an impact on the climate had strengthened. European Commission, Joint Research Centre (JRC) Emissions Database for Global Atmospheric Research (EDGAR) Continued emission of greenhouse gases will cause further warming and long-lasting changes in all components of the climate system, increasing the likelihood of severe, pervasive and irreversible impacts for people and ecosystems. * World Meteorological Organization, WMO Greenhouse Gas Bulletin No. Latest information on climate change This publication from the Australian Academy of Science aims to address confusion created by contradictory information in the public domain. Substitution of coal by natural gas however requires consideration of methane leakage, and 3% leakage means that the global warming potential from using gas is the same as burning coal. Relatively rapid global warming has occurred in the past. 15 (25 November 2019). While it is true that varying intensity of energy from the sun has driven long-term … With a doubling of overall electricity demand by then, and a carbon emission cost of $50 per tonne of CO2, nuclear's share of electricity generation is projected by IPCC to grow from 11% now to 18% of the increased demand. However, in many countries there are now programmes to reduce sulfur dioxide emissions from power stations, as these emissions cause acid rain. The evidence comes from direct measurements of rising surface air temperatures and subsurface ocean temperatures and from phenomena such as increases in average global sea levels, retreating glaciers, and changes to many physical and biological systems. It was released in October 2018 and said: An IPCC report from Working Groups I and II (physical science & impacts/adaptation) was released in September 2019, on The Ocean and Cryosphere in a Changing Climate. Thus nuclear power's contribution could increase to perhaps 30% of the global generation mix in 2030. -2. This is natural and what keeps the Earth habitable. CO2, with two bonds, absorbs some IR, but it is the next most abundant gas so its effect is significant. The major role of water vapour in absorbing thermal radiation is in some respects balanced by the fact that when condensed it causes an albedo effect which reflects about one-third of the incoming sunlight back into space. The Fourth Assessment Report in 2007 further reduced uncertainties and led to calls for action. World Meteorological Organization, Greenhouse Gas Bulletin #13 (30 October 2017) Intergovernmental Panel on Climate Change, Special Report: Global Warming of 1.5 °C (2018) In fact, study of the atmospheric carbon cycle shows that less than half of the anthropogenic emissions show up as increased carbon dioxide levels. Atmosphere and oceans are the focus of attention. It was set up as a partnership between the World Meteorological Organisation (WMO) and the UN Environment Program (UNEP) and 195 countries are members. Scientists have studied plausible pathways to a ‘Hothouse Earth’ scenario, where interacting tipping points could potentially lead to a cascading effect where Earth’s temperature heats up to a catastrophic 4-5 °C. At the beginning of that cooling (in the early Eocene), the global average temperature was about 6-7 ºC warmer than now. Intergovernmental Panel on Climate Change, Fourth Assessment Report (2007) Radiative forcing … Emissions of sulfates are increasingly constrained in most countries. The oceans have also warmed slightly, affecting the climate. Though Science Moms is nonpartisan and doesn't plan on backing political candidates, it does support policies like re-joining the Paris Agreement on Climate Change. If we want to protect our planet from dangerous and unprecedented change, first we must understand the science behind climate change. In 2018 it rose 2.3 ppm (0.8%), and about 3 ppm in 2019 – the largest annual increase yet observed. During the last decade many more measurements with higher accuracy have been made of temperatures in the upper layers of the ocean and in some parts of the deeper ocean. We’ll discuss flows of energy and carbon in Earth’s climate system, how climate models work, climate history, and future forecasts. President Joseph R. Biden Jr. brings with him the largest team of climate change experts ever assembled in the White House, and action on global warming is expected quickly. The combined radiative forcing due to increases in carbon dioxide, methane, nitrous oxide and halocarbons is +2.83 W/m. It also says: “Results from the best available climate models do not predict abrupt changes in such systems (often referred to as tipping points) in the near future. The Royal Society and the US National Academy of Sciences, Climate Change: Evidence & Causes (February 2014) The amount, extent and rate of this exceeds natural climate variability, some of the warmest years on record have been in the last decade. Smith et al, Anthropogenic sulfur dioxide emissions: 1850-2005, Atmospheric Chemistry and Physics, 11, 1101-1116 (2011) Freshening of the North Atlantic from the melting of the Greenland ice sheet is however, much less intense and hence is not expected to cause abrupt changes. On Wildfires and Climate Change, ‘The Science’ Got in the Way of the Science Exaggerating the role of global warming in U.S. wildfires only diverts attention from real solutions to … On this course you will explore this science, looking back across 4 billion years of Earth’s history to help you learn the difference between ‘natural’ from ‘human’ induced change; looking to the present to see how the impacts of climate change … Warming also heats the ocean, causing the water to expand and the sea level to rise. Contribution of Working Groups I, II and III to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change, Core Writing Team, R. K. Pachauri, L. A. Meyer, Eds. This course will give you the knowledge you need, and practice communicating about climate change. Diatomic molecules, like O2 and N2 which mostly make up our atmosphere, absorb very little IR. The current warming trend is of particular significance because most of it is extremely likely (greater than 95% probability) to be the result of human activity since the mid-20 th century and proceeding at a rate that is unprecedented over decades to millennia. More intense and longer droughts have been observed over wider areas since the 1970s, particularly in the tropics and subtropics. Electricity generation is one of the major sources of carbon dioxide emissions, providing about one-third of the total and one-half of the increase expected 2005-30. Limiting warming to 1.5 °C is not physically impossible but would require unprecedented transitions in all aspects of society. The second covers the impacts of climate change, the options for adaptation and identifies where people and the environment are most vulnerable. World Meteorological Organization, United in Science – High-level synthesis report of latest climate science information convened by the Science Advisory Group of the UN Climate Action Summit 2019 Climate Change 2013: The Physical Science Basis The Working Group I contribution to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC) provides a comprehensive assessment of the physical science basis of climate change since 2007 when the Fourth Assessment Report (AR4) was released. However, as warming increases, the possibilities of major abrupt change cannot be ruled out.” However, “the climate system involves many competing processes that could switch the climate into a different state once a threshold has been exceeded. Developing countries now account for some 55% of CO2 emissions. Recent climate changes have had widespread impacts on human and natural systems. 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