Climate change is the current rapid warming of the Earth’s climate caused by person activity. If left unchecked (and current responses are doing little to halt it) it poses an unprecedented danger to person civilisation additionally the ecosystems on this planet.<\/p>\n
First, ‚climate‘ is very distinctive from ‚weather‘. Weather changes by the hour and, especially in the UK, naturally varies widely between years. We know the climate is changing because, averaged out over longer periods, the global mean temperature has been consistently rising, across land and sea. It is now about 0.8C above pre-industrial times.<\/p>\n
The below graph shows global temperatures from 1860 to 2015. The data used came from the National Oceanic and Atmospheric Administration (NOAA). For more information, just click here.<\/p>\n
Climate Lab Book created an animated climate spiral, illustrating the increase in global temperatures from 1850 to the present.<\/p>\n
The entire world was experiencing changes in climates, affecting millions of lives. Already, there has been the bleaching of coral reefs, the sea ice volume in the Arctic has been reaching new lows, an increase in the number of natural disasters worldwide (such as wildifres, droughts, floods) additionally the mass migration of species. For more information, it is possible to read more about the current aftereffects of climate change here.<\/p>\n
Certain gases in the Earth’s atmosphere (water vapour, CO2, methane and others) allow sunlight to pass through, but then stop the heat from escaping back out into space – much like glass in a greenhouse. Without this, our planet would be uninhabitable to most forms of life. However, by changing the balance of gases in the atmosphere, humans have increased the greenhouse effect, causing the rising temperatures we now see.<\/p>\n
As explained above, these gases exist naturally in our atmosphere. The most significant increases are in carbon dioxide ( there is now over a third more CO2 in our atmosphere than there was before the industrial revolution) and methane. Methane is a more potent greenhouse gas, but it only remains in the atmosphere for about a decade. Carbon dioxide lasts for about 100 years or more, so even though we stopped emissions from person activities altogether, the planet would continue to warm up from the gases already emitted. The main causes of increased CO2 in the atmosphere are burning fossil fuels (coal, oil and gas), and deforestation and other changes in land use that release stored CO2 and methane.<\/p>\n
The below graph, also known as the Keeling Curve, shows CO2 levels today and how this compares with the last 10,000 years.<\/p>\n
The idea of an urgent shift away from fossil fuels is not welcome to every person, and those who seek to delay or prevent this were very successful in spreading the idea that climate scientists are uncertain about climate change (or even fraudulent!). Unfortunately there was, as legal terminology has it, no ‚reasonable doubt‘ about climate change.<\/p>\n
Could the rise in atmospheric carbon be coming from somewhere else?<\/strong><\/p>\n Humans are currently emitting around 30 billion tonnes of CO2 into the atmosphere every year. Of course, maybe it’s coincidence that CO2 levels are rising so sharply at the same time so let’s look at more evidence that we’re responsible for the rise in CO2 levels:<\/p>\n How do we know that the extra CO2 in the atmosphere is warming the planet through the greenhouse effect?<\/strong><\/p>\n ( The above Q&A was taken from Skeptical Science, where you can read more about the evidence and find the answers to lots more questions like „Could the sun be causing it?“ and “ What about the Mediaeval warm period?“)<\/p>\n That is dependent upon what we do now. Because of all the greenhouse gases already in the atmosphere, if the human race died out tomorrow, we’d still expect the planet to continue heating up. If we carry on emitting at the rate we are today, it will heat up so much more rapidly. Rather than just warming, it makes more sense to think of it while the climate becoming more unstable, with extra energy in the system. Extreme weather events will become more common, ecosystems is likely to be put under stress and so will person agriculture and water supplies. Some parts of the world are particularly vulnerable, such as sub-Saharan Africa, but no area is likely to be immune.<\/p>\n The pledges that governments have made so far to cut emissions are insufficient. Even if implemented fully, they have been consistent with an average global temperature rise of 4C (see, e.g. the IEA). However, there are now concerns that global temperatures could rise at a greater rate due to the Earth’s climate sensitivity being non-linear. A rise of 2C has been viewed as a ‚safe limit‘ in international negotiations, but this does not fully take into account either the serious humanitarian and ecosystem impacts of this temperature rise in many parts of the world. The poorest countries of the world and small island states face threats, for the latter to their actual existence, with any global warming above 1.5°C. Nor does it consider the risk of triggering positive feedback mechanisms. An example of the latter is the release of frozen carbon and methane from melting in the polar regions, which would further accelerate warming. Since there is in reality no clear ‚safe‘ zone, this demands an even more urgent response to cutting emissions.<\/p>\n There is a vast amount of information on the internet about the science of climate change, from the simple to the deeply technical, and some which can be just plain wrong ( find out more about climate sceptics). For example, here is a brief introduction to climate science and further discussion of the climate danger.<\/p>\n ‚Climate Emergency‘, written by the campaign’s former National Coordinator, Phil Thornhill, is a good introduction to important concepts in the science of climate change.<\/p>\n For an explanation of where we are heading, look at the presentation ‚Climate Change: Going Beyond Dangerous‘ by Professor Kevin Anderson.<\/p>\n More on the impacts of climate change from the entire world Bank: ‚Turn Down the Heat: Why a 4°c warmer world must be Avoided‘<\/p>\n Climate change<\/strong>, periodic modification of Earth’s climate brought about as a result of changes in the atmosphere as well as interactions between the atmosphere and various other geologic, chemical, biological, and geographic factors within the Earth system.<\/p>\n A series of photographs of the Grinnell Glacier taken from the summit of Mount Gould in Glacier National Park, Montana, in 1938, 1981, 1998, and 2006 (from left to right). In 1938 the Grinnell Glacier filled the entire area at the image. By 2006 it had largely disappeared from this view.1938-T.J. Hileman\/Glacier National Park Archives, 1981 – Carl Key\/USGS, 1998 – Dan Fagre\/USGS, 2006 – Karen Holzer\/USGS The atmosphere is a dynamic fluid that is continually in motion. Both its physical properties and its rate and direction of motion are influenced by a variety of factors, including solar radiation, the geographic position of continents, ocean currents, the location and orientation of mountain ranges, atmospheric chemistry, and vegetation growing on the land surface. Every one of these factors change through time. Some factors, such as the distribution of heat within the oceans, atmospheric chemistry, and surface vegetation, change at very short timescales. Others, such as the position of continents additionally the location and height of mountain ranges, change over very long timescales. Therefore, climate, which results from the physical properties and motion of the atmosphere, varies at every conceivable timescale.<\/p>\n climate change: timeline<\/strong>A timeline of important developments in climate change.Encyclopædia Britannica, Inc.\/Patrick O’Neill Riley<\/p>\n Climate is often defined loosely due to the fact average weather at a particular place, incorporating such features as temperature, precipitation, humidity, and windiness. A more specific definition would state that climate is the mean state and variability of these features over some extended time period. Both definitions acknowledge that the weather is always changing, owing to instabilities in the atmosphere. And as weather varies from day to day, so too does climate vary, from daily day-and-night cycles up to periods of geologic time hundreds of millions of years long. In a very real sense, climate variation is a redundant expression—climate is always varying. No two years are exactly alike, nor are any two decades, any two centuries, or any two millennia.<\/p>\n This article addresses the concept of climatic variation and change within the set of integrated natural features and processes known as the Earth system. The nature of the evidence for climate change is explained, as are the principal mechanisms that have caused climate change throughout the history of Earth. Finally, a detailed description is given of climate change over many different timescales, ranging from a typical person life span to all of geologic time. For a detailed description of the development of Earth’s atmosphere, see the article atmosphere, evolution of. For full treatment of the absolute most critical issue of climate change in the contemporary world, see global warming.<\/p>\n Get exclusive access to content from our 1768 First Edition with your subscription.Subscribe today<\/p>\n The atmosphere is influenced by and linked to other top features of Earth, including oceans, ice masses (glaciers and sea ice), land surfaces, and vegetation. Together, they make up an integrated Earth system, in which all components interact with and influence one another in often complex ways. As an example, climate influences the distribution of vegetation on Earth’s surface ( e.g., deserts exist in arid regions, forests in humid regions), but vegetation in turn influences climate by reflecting radiant energy back into the atmosphere, transferring water (and latent heat) from soil to the atmosphere, and influencing the horizontal movement of air across the land surface.<\/p>\n iceberg<\/strong>Tourist ship in front of a massive iceberg near the coast of Greenland.Paul Zizka\/Visit Greenland (Visitgreenland.com) Earth scientists and atmospheric scientists are still seeking a full understanding of the complex feedbacks and interactions among the various components of the Earth system. This effort is being facilitated by the development of an interdisciplinary science called Earth system science. Earth system science is composed of a wide range of disciplines, including climatology ( the study of the atmosphere), geology ( the study of Earth’s surface and underground processes), ecology ( the study of how Earth’s organisms relate with one another and their environment), oceanography ( the study of Earth’s oceans), glaciology ( the study of Earth’s ice masses), and even the social sciences ( the study of human being behaviour in its social and cultural aspects).<\/p>\n A full understanding of the Earth system requires knowledge of how the system and its components have changed through time. The pursuit of this understanding has led to development of Earth system history, an interdisciplinary science that includes not only the contributions of Earth system scientists but also paleontologists (who study the life of past geologic periods), paleoclimatologists (who study past climates), paleoecologists (who study past environments and ecosystems), paleoceanographers (who study the history of the oceans), and other scientists concerned with Earth history. Because different components of the Earth system change at different rates and so are relevant at different timescales, Earth system history is a diverse and complex science. Students of Earth system history are not just concerned with documenting what has happened; they also view the past as a group of experiments in which solar radiation, ocean currents, continental configurations, atmospheric chemistry, and other important features have varied. These experiments provide opportunities to learn the relative influences of and interactions between various components of the Earth system. Studies of Earth system history also global warming introduction paragraph<\/a> specify the full array of states the system has experienced in the past and those the system is capable of experiencing in the foreseeable future.<\/p>\n Certainly, people have always been aware of climatic variation at the relatively short timescales of seasons, years, and decades. Biblical scripture and other early documents refer to droughts, floods, periods of severe cold, and other climatic events. Nevertheless, a full appreciation of the nature and magnitude of climatic change did not come about until the late 18th and early 19th centuries, a time if the widespread recognition of the deep antiquity of Earth occurred. Naturalists of this time, including Scottish geologist Charles Lyell, Swiss-born naturalist and geologist Louis Agassiz, English naturalist Charles Darwin, American botanist Asa Gray, and Welsh naturalist Alfred Russel Wallace, came to recognize geologic and biogeographic evidence that made sense only in the light of past climates radically different from those prevailing today.<\/p>\n Long-term data sets reveal increased concentrations of the greenhouse gas carbon dioxide in Earth’s atmosphere<\/strong>John P. Rafferty, biological and earth science editor of Encyclopædia Britannica, discussing carbon dioxide and its relationship to warming conditions at Earth’s surface.Encyclopædia Britannica, Inc.See all videos for this article<\/p>\n Geologists and paleontologists in the 19th and early 20th centuries uncovered evidence of massive climatic changes taking place before the Pleistocene—that is, before some 2.6 million years ago. For example, red beds indicated aridity in regions that are now humid ( e.g., England and New England), whereas fossils of coal-swamp plants and reef corals indicated that tropical climates once occurred at present-day high latitudes in both Europe and North America. Since the late 20th century the development of advanced technologies for dating rocks, together with geochemical techniques and other analytical tools, have revolutionized the understanding of early Earth system history.<\/p>\n The occurrence of multiple epochs in recent Earth history during which continental glaciers, developed at high latitudes, penetrated into northern Europe and eastern North America was recognized by scientists by the late 19th century. Scottish geologist James Croll proposed that recurring variations in orbital eccentricity (the deviation of Earth’s orbit from a perfectly circular path) were responsible for alternating glacial and interglacial periods. Croll’s controversial idea was taken up by Serbian mathematician and astronomer Milutin Milankovitch in the early 20th century. Milankovitch proposed that the system that brought about periods of glaciation was driven by cyclic changes in eccentricity as well as two other orbital parameters: precession (a change in the directional focus of Earth’s axis of rotation) and axial tilt (a change in the inclination of Earth’s axis with respect to the plane of its orbit around the Sun). Orbital variation is now recognized as a important driver of climatic variation throughout Earth’s history (see below Orbital [Milankovitch] variations).<\/p>\n The precession of Earth’s axis.Encyclopædia Britannica, Inc.\n
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What can we expect to happen next?<\/h2>\n
What would world 4C hotter look like?<\/h2>\n
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Read more<\/h2>\n
\nBRITANNICA EXPLORES EARTH’S TO-DO LIST
\nPerson action has triggered a vast cascade of environmental problems that now threaten the continued ability of both natural and person systems to flourish. Solving the critical environmental problems of global warming, water scarcity, pollution, and biodiversity loss are perhaps the greatest challenges of the 21st century. Will we rise to meet them?<\/p>\nThe Earth System<\/h2>\n
\nTurkmenistan<\/strong>Drought-resistant plants grow in the Repetek Preserve in the southeastern Karakum Desert, Turkmenistan.© Rodger Jackman\/Oxford Scientific Films Ltd.
\nDeciduous forest in fall coloration, Wasatch Mountains, Utah.Dorothea W. Woodruff\/Encyclopædia Britannica, Inc.<\/p>\n
\nClimate change
\nCAUSES<\/p>\n