query: Rapid assessment of average temperatures in France between 26-28 June showed a “substantial” increase in the likelihood of the heatwave happening as a result of human-caused global warming, experts at the World Weather Attribution group said.

positive: Attribution of recent climate change Attribution of recent climate change is the effort to scientifically ascertain mechanisms responsible for recent climate changes on Earth , commonly known as ` global warming ' . The effort has focused on changes observed during the period of instrumental temperature record , when records are most reliable ; particularly in the last 50 years , when human activity has grown fastest and observations of the troposphere have become available . The dominant mechanisms are anthropogenic , i.e. , the result of human activity . They are :  increasing atmospheric concentrations of greenhouse gases  global changes to land surface , such as deforestation  increasing atmospheric concentrations of aerosols .   There are also natural mechanisms for variation including climate oscillations , changes in solar activity , and volcanic activity .   According to the Intergovernmental Panel on Climate Change ( IPCC ) , it is `` extremely likely '' that human influence was the dominant cause of global warming between 1951 and 2010 . The IPCC defines `` extremely likely '' as indicating a probability of 95 to 100 % , based on an expert assessment of all the available evidence .   Multiple lines of evidence support attribution of recent climate change to human activities :  A basic physical understanding of the climate system : greenhouse gas concentrations have increased and their warming properties are well-established .  Historical estimates of past climate changes suggest that the recent changes in global surface temperature are unusual .  Computer-based climate models are unable to replicate the observed warming unless human greenhouse gas emissions are included .  Natural forces alone ( such as solar and volcanic activity ) can not explain the observed warming .   The IPCC 's attribution of recent global warming to human activities is a view shared by the scientific community , and is also supported by 196 other scientific organizations worldwide ( see also : scientific opinion on climate change ) .

positive: Scientific consensus on climate change There is currently a strong scientific consensus that the Earth is warming and that this warming is mainly caused by human activities. This consensus is supported by various studies of scientists' opinions and by position statements of scientific organizations, many of which explicitly agree with the Intergovernmental Panel on Climate Change (IPCC) synthesis reports.  Nearly all actively publishing climate scientists (97–98%) support the consensus on anthropogenic climate change, and the remaining 2% of contrarian studies either cannot be replicated or contain errors.

negative: Regional effects of global warming Regional effects of global warming are long-term significant changes in the expected patterns of average weather of a specific region due to global warming . The world average temperature is rising due to the greenhouse effect caused by increasing levels of greenhouse gases , especially carbon dioxide . When the global temperature changes , the changes in climate are not expected to be uniform across the Earth . In particular , land areas change more quickly than oceans , and northern high latitudes change more quickly than the tropics , and the margins of biome regions change faster than do their cores .   Regional effects of global warming vary in nature . Some are the result of a generalised global change , such as rising temperature , resulting in local effects , such as melting ice . In other cases , a change may be related to a change in a particular ocean current or weather system . In such cases , the regional effect may be disproportionate and will not necessarily follow the global trend . The increasing temperatures from greenhouse gases have been causing sea levels to rise for many years .   There are three major ways in which global warming will make changes to regional climate : melting or forming ice , changing the hydrological cycle ( of evaporation and precipitation ) and changing currents in the oceans and air flows in the atmosphere . The coast can also be considered a region , and will suffer severe impacts from sea level rise .

negative: 2013 heatwave in Ireland and the United Kingdom The 2013 heat wave in the United Kingdom and Ireland was a period of unusually hot weather primarily in July 2013 , with isolated warm days in June and August . A prolonged high pressure system over Britain and Ireland caused higher than average temperatures for 19 consecutive days in July , reaching 33.5 ° C at Heathrow and Northolt . Following a brief period of cooler weather at the end of July , temperatures temporarily rose again , peaking at 34.1 ° C on 1 August in the United Kingdom , the warmest the country had seen since July 2006 , and 31.0 ° C in Ireland . At 19 days , the July heatwave was the longest continuous period of hot weather in the UK since August 1997 .   However , in the general sense , Britain did not have an overall exceptional summer ; the country experienced cool low pressure systems brought by an unseasonably low latitude by the jet stream for the 6 summers previous , which made the summer of 2013 more `` welcome '' and feel warmer than other summers . The historical records suggests `` Using the CET record ( for June , July & August ) , the average temperature by that measure was 16.3 degC ( Provisional ) : neither June nor August was exceptionally warm , so this value does not ` rate ' too highly when set against other very warm summer seasons . '' With June being a cool month and August being an Average month , in terms of temperatures the English Central summer temperature ended up being on the average side set up against previous summers since the CET series began in 1659 .

negative: Angry Summer The Australian summer of 2012 -- 2013 , known as the Angry Summer or Extreme Summer , resulted in 123 weather records being broken over a 90-day period , including the hottest day ever recorded for Australia as a whole , the hottest January on record , the hottest summer average on record , and a record seven days in a row when the whole continent averaged above 39 ° C. Single-day temperature records were broken in dozens of towns and cities , as well as single-day rainfall records , and several rivers flooded to new record highs .   In January 2013 , the Bureau of Meteorology altered its weather forecasting chart 's temperature scale to include a range , coloured purple , between 52 ° and 54 ° C . The reporting of the heatwave in the Australian media attracted controversy in the scientific community , as very few articles cited a correlation between the event and climate change , which it was correlated with according to studies conducted by the University of Melbourne .

negative: 2010 Northern Hemisphere heat waves The 2010 Northern Hemisphere summer heat waves included severe heat waves that impacted most of the United States, Kazakhstan, Mongolia, China, Hong Kong, North Africa and the European continent as a whole, along with parts of Canada, Russia, Indochina, South Korea and Japan during May, June, July, and August 2010. The first phase of the global heatwaves was caused by a moderate El Niño event, which lasted from June 2009 to May 2010. The first phase lasted only from April 2010 to June 2010, and caused only moderate above average temperatures in the areas affected. But it also set new record high temperatures for most of the area affected, in the Northern Hemisphere. The second phase (the main, and most devastating phase) was caused by a very strong La Niña event, which lasted from June 2010 to June 2011. According to meteorologists, the 2010–11 La Niña event was one of the strongest La Niña events ever observed. That same La Niña event also had devastating effects in the Eastern states of Australia. The second phase lasted from June 2010 to October 2010, caused severe heat waves, and multiple record-breaking temperatures. The heatwaves began on April 2010, when strong anticyclones began to develop, over most of the affected regions, in the Northern Hemisphere. The heatwaves ended in October 2010, when the powerful anticyclones over most of the affected areas dissipated. The heat wave during the summer of 2010 was at its worst in June, over the Eastern United States, Middle East, Eastern Europe and European Russia, and over Northeastern China and southeastern Russia. June 2010 marked the fourth consecutive warmest month on record globally, at 0.66 °C (1.22 °F) above average, while the period April–June was the warmest ever recorded for land areas in the Northern Hemisphere, at 1.25 °C (2.25 °F) above average. The previous record for the global average temperature in June was set in 2005 at 0.66 °C (1.19 °F), and the previous warm record for April–June over Northern Hemisphere land areas was 1.16 °C (2.09 °F), set in 2007. The strongest of the anticyclones, the one situated over Siberia, registered a maximum high pressure of 1040 millibars. The weather caused forest fires in China, where three in a team of 300 died fighting a fire that broke out in the Binchuan County of Dali, as Yunnan suffered the worst drought in 60 years by February 17. A major drought was reported across the Sahel as early as January. In August, a section of the Petermann Glacier tongue connecting northern Greenland, the Nares Strait and the Arctic Ocean broke off, the biggest ice shelf in the Arctic to detach in 48 years. By the time the heatwaves had ended in late October 2010, about $500 billion (2011 USD) of damage was done, in the Northern Hemisphere alone. The World Meteorological Organization stated that the heat waves, droughts and flooding events fit with predictions based on global warming for the 21st century, include those based on the Intergovernmental Panel on Climate Change's 2007 4th Assessment Report. Some climatologists argue that these weather events would not have happened if the atmospheric carbon dioxide was at pre-industrial levels.

negative: Hurricane Katrina and global warming The tremendous destruction caused by recent Atlantic Ocean tropical cyclones , such as Hurricanes Katrina , Wilma , and Sandy caused a substantial upsurge in interest in the subject of global warming by news media and the wider public , and concerns that global climatic change may have played a significant role in those events . Time Magazine , for example , published an article titled , `` Is Global Warming Fueling Katrina ? '' -- however , the article itself addressed hurricanes in general , rather than Katrina specifically , and was inconclusive .   Shortly after the hurricane , former Boston Globe reporter Ross Gelbspan wrote an op-ed piece for the Globe titled , `` Katrina 's Real Name '' , declaring that the hurricane 's `` real name is global warming . '' Gelbspan went on to assert :  `` Although Katrina began as a relatively small hurricane that glanced off south Florida , it was supercharged with extraordinary intensity by the relatively blistering sea surface temperatures in the Gulf of Mexico . ''  Gelbspan did not single out Katrina from other recent storms in that regard ; in the article he went on to attribute other major weather events over the preceding year to global warming , including a blizzard in Los Angeles , high winds in Scandinavia , wildfires in Spain , and a drought centered in Missouri .   Britain 's then deputy prime minister , John Prescott , has linked Katrina with global warming , and statements made shortly after the hurricane by Germany 's environment minister , Jürgen Trittin , indicate he believes that global warming is responsible for an increase in the frequency of destructive natural events .   Kerry Emanuel had recently published a paper in the journal Nature that found a good correlation between hurricane intensity and sea surface temperatures . Some journalists have claimed Emanuel 's paper concludes that the recent increase in intense Atlantic storms is due to global warming , but Emanuel stated that `` it would be absurd to attribute the Katrina disaster to global warming '' .   The Internet blog RealClimate has written that `` there is no way to prove that Katrina either was , or was not , affected by global warming '' .

negative: IPCC First Assessment Report The First Assessment Report ( FAR ) of the Intergovernmental Panel on Climate Change ( IPCC ) was completed in 1990 . It served as the basis of the United Nations Framework Convention on Climate Change ( UNFCCC ) .   The report was issued in three main sections , corresponding to the three Working Groups of scientists that the IPCC had established .   Working Group I : Scientific Assessment of Climate Change , edited by J.T. Houghton , G.J. Jenkins and J.J. Ephraums  Working Group II : Impacts Assessment of Climate Change , edited by W.J. McG . Tegart , G.W. Sheldon and D.C. Griffiths  Working Group III : The IPCC Response Strategies   Each section included a summary for policymakers . This format was followed in subsequent Assessment Reports .   The executive summary of the policymakers ' summary of the WG I report includes :   We are certain of the following : there is a natural greenhouse effect ... ; emissions resulting from human activities are substantially increasing the atmospheric concentrations of the greenhouse gases : CO2 , methane , CFCs and nitrous oxide . These increases will enhance the greenhouse effect , resulting on average in an additional warming of the Earth 's surface . The main greenhouse gas , water vapour , will increase in response to global warming and further enhance it .  We calculate with confidence that : ... CO2 has been responsible for over half the enhanced greenhouse effect ; long-lived gases would require immediate reductions in emissions from human activities of over 60 % to stabilise their concentrations at today 's levels ...  Based on current models , we predict : under -LSB- BAU -RSB- increase of global mean temperature during the -LSB- 21st -RSB- century of about 0.3 oC per decade ( with an uncertainty range of 0.2 to 0.5 oC per decade ) ; this is greater than that seen over the past 10,000 years ; under other ... scenarios which assume progressively increasing levels of controls , rates of increase in global mean temperature of about 0.2 oC -LSB- to -RSB- about 0.1 oC per decade .  There are many uncertainties in our predictions particularly with regard to the timing , magnitude and regional patterns of climate change , due to our incomplete understanding of : sources and sinks of GHGs ; clouds ; oceans ; polar ice sheets .  Our judgement is that : global mean surface air temperature has increased by 0.3 to 0.6 oC over the last 100 years ... ; The size of this warming is broadly consistent with predictions of climate models , but it is also of the same magnitude as natural climate variability . Thus the observed increase could be largely due to this natural variability ; alternatively this variability and other human factors could have offset a still larger human-induced greenhouse warming . The unequivocal detection of the enhanced greenhouse effect is not likely for a decade or more .  under the IPCC business as usual emissions scenario , an average rate of global mean sea level rise of about 6 cm per decade over the next century ( with an uncertainty range of 3 -- 10 cm per decade ) , mainly due to thermal expansion of the oceans and the melting of some land ice . The predicted rise is about 20 cm ... by 2030 , and 65 cm by the end of the next century .

negative: Climate change Climate change is a change in the statistical distribution of weather patterns when that change lasts for an extended period of time ( i.e. , decades to millions of years ) . Climate change may refer to a change in average weather conditions , or in the time variation of weather around longer-term average conditions ( i.e. , more or fewer extreme weather events ) . Climate change is caused by factors such as biotic processes , variations in solar radiation received by Earth , plate tectonics , and volcanic eruptions . Certain human activities have been identified as primary causes of ongoing climate change , often referred to as global warming .   Scientists actively work to understand past and future climate by using observations and theoretical models . A climate record -- extending deep into the Earth 's past -- has been assembled , and continues to be built up , based on geological evidence from borehole temperature profiles , cores removed from deep accumulations of ice , floral and faunal records , glacial and periglacial processes , stable-isotope and other analyses of sediment layers , and records of past sea levels . More recent data are provided by the instrumental record . General circulation models , based on the physical sciences , are often used in theoretical approaches to match past climate data , make future projections , and link causes and effects in climate change .

negative: Kerry Emanuel Kerry Andrew Emanuel ( born April 21 , 1955 ) is an American professor of meteorology currently working at the Massachusetts Institute of Technology in Cambridge . In particular he has specialized in atmospheric convection and the mechanisms acting to intensify hurricanes .  He was named one of the Time 100 influential people of 2006 .  In 2007 , he was elected as a member of the U.S. National Academy of Sciences .   He hypothesized in 1994 about a superpowerful type of hurricane which could be formed if average sea surface temperature increased another 15C more than it 's ever been ( see `` hypercane '' ) .   In a March 2008 paper published in the Bulletin of the American Meteorological Society , he put forward the conclusion that global warming is likely to increase the intensity but decrease the frequency of hurricane and cyclone activity . Gabriel Vecchi , of NOAA said of Emanuel 's announcement , `` While his results do n't rule out the possibility that global warming has contributed to the recent increase in activity in the Atlantic , they suggest that other factors -- possibly in addition to global warming -- are likely to have been substantial contributors to the observed increase in activity . ''   In 2013 , with other leading experts , he was co-author of an open letter to policy makers , which stated that `` continued opposition to nuclear power threatens humanity 's ability to avoid dangerous climate change . ''

negative: Extreme weather Extreme weather includes unexpectable , unusual , unpredictable severe or unseasonal weather ; weather at the extremes of the historical distribution -- the range that has been seen in the past . Often , extreme events are based on a location 's recorded weather history and defined as lying in the most unusual ten percent . In recent years some extreme weather events have been attributed to human-induced global warming , with studies indicating an increasing threat from extreme weather in the future .

negative: Thermal runaway Thermal runaway occurs in situations where an increase in temperature changes the conditions in a way that causes a further increase in temperature , often leading to a destructive result . It is a kind of uncontrolled positive feedback .   In other words , `` thermal runaway '' describes a process which is accelerated by increased temperature , in turn releasing energy that further increases temperature . In chemistry ( and chemical engineering ) , it is associated with strongly exothermic reactions that are accelerated by temperature rise . In electrical engineering , thermal runaway is typically associated with increased current flow and power dissipation , although exothermic chemical reactions can be of concern here too . Thermal runaway can occur in civil engineering , notably when the heat released by large amounts of curing concrete is not controlled -LCB- Citation needed -RCB- . In astrophysics , runaway nuclear fusion reactions in stars can lead to nova and several types of supernova explosions , and also occur as a less dramatic event in the normal evolution of solar mass stars , the `` helium flash '' .   There are also concerns regarding global warming that a global average increase of 3 -- 4 degrees Celsius above the preindustrial baseline could lead to a further unchecked increase in surface temperatures . For example , releases of methane , a greenhouse gas more potent than CO2 , from wetlands , melting permafrost and continental margin seabed clathrate deposits could be subject to positive feedback .

negative: Global warming hiatus A global warming hiatus , also sometimes referred to as a global warming pause or a global warming slowdown , is a period of relatively little change in globally averaged surface temperatures . In the current episode of global warming many such 15-year periods appear in the surface temperature record , along with robust evidence of the long-term warming trend ; climate is classically averaged over 30-year periods .   Publicity has surrounded claims of a global warming hiatus during the period 1998 -- 2013 . The exceptionally warm El Niño year of 1998 was an outlier from the continuing temperature trend , and so subsequent annual temperatures gave the appearance of a hiatus : by January 2006 , it appeared to some that global warming had stopped or paused . A 2009 study showed that decades without warming were not exceptional , and in 2011 a study showed that if allowances were made for known variability , the rising temperature trend continued unabated . There was increased public interest in 2013 in the run-up to publication of the IPCC Fifth Assessment Report , and despite concerns that a 15-year period was too short to determine a meaningful trend , the IPCC included a section on a hiatus , which it defined as a much smaller increasing linear trend over the 15 years from 1998 to 2012 , than over the 60 years from 1951 to 2012 . Various studies examined possible causes of the short-term slowdown . Even though the overall climate system has continued to accumulate energy due to Earth 's positive energy budget , the available temperature readings at the Earth 's surface indicate slower rates of increase in surface warming than in the prior decade . Since measurements at the top of the atmosphere show that Earth is receiving more energy than it is radiating back into space , the retained energy should be producing warming in the Earth 's climate system .   Research reported in July 2015 on an updated NOAA dataset casts doubt on the existence of a hiatus , and it finds no indication of a slowdown even in earlier years . Scientists working on other datasets welcomed this study , though they have expressed the view that the recent warming trend was less than in previous periods of the same length . Subsequently , a detailed study supports the conclusion that warming is continuing , but it also find there was less warming between 2001 and 2010 than climate models had predicted , and that this slowdown might be attributed to short-term variations in the Pacific decadal oscillation ( PDO ) , which was negative during that period . Another review finds `` no substantive evidence '' of a pause in global warming . A statistical study of global temperature data since 1970 concludes that the term ` hiatus ' or ` pause ' is not justified .   Independent of these discussions about data and measurements for earlier years , 2015 turned out to be much warmer than any of the earlier years , already before El Niño conditions started . The warmth of 2015 largely ended any remaining scientific credibility of claims that the supposed `` hiatus '' since 1998 had any significance for the long-term warming trend . In January 2017 , a study published in the journal Science Advances cast further doubt on the existence of a recent pause , with more evidence that ocean temperatures have been underestimated . An April 2017 study found the data consistent with a steady warming trend globally since the 1970s , with fluctuations within the expected range of short term variability .

negative: Climate change in southeast Alaska Climate change in southeast Alaska are changes which occur in southeast Alaska as average temperatures rise as a result of global warming .   The temperate rainforest that covers this area is a result of humid summers and transient snow cover in winter . The conifers that thrive in this moist climate are free from fire risk as compared to the forests to both the north and south .   Warmer weather will lengthen the growing period of the trees and the increase in evapotranspiration is likely to outweigh the increase of precipitation . Assuming a scenario involving a mid-range increase in emissions , the average temperature may rise by about 3 ° F by the year 2040 and by 6 ° F by 2080 . The trees will grow more vigorously but fungi that cause rot will also thrive , there is likely to be an increase in windthrow , and fire risk may rise .   With winter temperatures increasing , the type of precipitation will change . Lack of snow cover on the ground will expose tree roots to colder soils , and yellow ceder is already showing the result of this with many trees dying . The melting of glaciers in the watershed is likely to accelerate and will cause hydrological changes that will impact the wetland habitats and the distribution of wildlife . Animals such as the black-tailed deer , moose and mountain goat may benefit from less snow cover , while such mammals as the northwestern deer mouse that tunnels under the snow are likely to be disadvantaged .

negative: List of scientists opposing the mainstream scientific assessment of global warming This is a list of scientists who have made statements that conflict with the scientific consensus on global warming as summarized by the Intergovernmental Panel on Climate Change and endorsed by other scientific bodies . As approximately 97 % of publishing climate scientists support the consensus on anthropogenic climate change , this list represents a minority viewpoint .   The scientific consensus is that the global average surface temperature has risen over the last century . Scientific opinion on climate change was summarized in the 2001 Third Assessment Report of the Intergovernmental Panel on Climate Change ( IPCC ) . The main conclusions on global warming at that time were as follows :  The global average surface temperature has risen 0.6 ± 0.2 ° C since the late 19th century , and 0.17 ° C per decade in the last 30 years .  `` There is new and stronger evidence that most of the warming observed over the last 50 years is attributable to human activities '' , in particular emissions of the greenhouse gases carbon dioxide and methane .  If greenhouse gas emissions continue the warming will also continue , with temperatures projected to increase by 1.4 ° C to 5.8 ° C between 1990 and 2100 . Accompanying this temperature increase will be increases in some types of extreme weather and a projected sea level rise . The balance of impacts of global warming become significantly negative at larger values of warming .   These findings are recognized by the national science academies of all the major industrialized nations ; the consensus has strengthened over time and is now virtually unanimous . The level of consensus correlates with expertise in climate science .   There have been several efforts to compile lists of dissenting scientists , including a 2008 US senate minority report , the Oregon Petition , and a 2007 list by the Heartland Institute , all three of which have been criticized on a number of grounds .   For the purpose of this list , a `` scientist '' is defined as an individual who has published at least one peer-reviewed research article in the broad field of natural sciences , although not necessarily in a field relevant to climatology . Since the publication of the IPCC Third Assessment Report , each has made a clear statement in his or her own words ( as opposed to the name being found on a petition , etc. ) disagreeing with one or more of the report 's three main conclusions . Their views on climate change are usually described in more detail in their biographical articles . Few of the statements in the references for this list are part of the peer-reviewed scientific literature ; most are from other sources such as interviews , opinion pieces , online essays and presentations .   NB : Only individuals who have their own Wikipedia article may be included in the list .

negative: Effects of global warming on marine mammals The effect of global warming on marine mammals is a growing concern . Many of the effects of climate change are currently unknown due to its unpredictability , but many are becoming increasingly evident today . Some effects are very direct such as loss of habitat , temperature stress , and exposure to severe weather . Other effects are more indirect such as changes in host pathogen associations , changes in body condition because of predator -- prey interaction , changed in exposure to toxins , and increased human interactions . These are just a few examples of what marine mammals are dealing with as a result of rapid climate change . There are a number of marine mammals that have been affected by climate change including walruses , seals , penguins , and polar bears .

negative: Runaway climate change Runaway climate change or runaway global warming is hypothesized to follow a tipping point in the climate system , after accumulated climate change initiates a reinforcing positive feedback . This is thought to cause the climate to rapidly change until it reaches a new stable condition . These phrases may be used with reference to concerns about rapid global warming . Some astronomers use the expression runaway greenhouse effect to describe a situation where the climate deviates catastrophically and permanently from the original state -- as happened on Venus .   Although these terms are rarely used in the peer-reviewed climatological literature , that literature does use the similar phrase `` runaway greenhouse effect '' , which refers specifically to climate changes that cause a planetary body 's water to boil off .

negative: Warm antibody autoimmune hemolytic anemia Warm antibody autoimmune hemolytic anemia ( WAIHA ) is the most common form of autoimmune hemolytic anemia . About half of the cases are of unknown cause , with the other half attributable to a predisposing condition or medications being taken . Contrary to cold autoimmune hemolytic anemia ( e.g. , cold agglutinin disease and paroxysmal cold hemoglobinuria ) which happens in cold temperature ( 28 -- 31 ° C ) , WAIHA happens in body temperature .

negative: IPCC Third Assessment Report The IPCC Third Assessment Report , Climate Change 2001 , is an assessment of available scientific and socio-economic information on climate change by the IPCC . The IPCC was established in 1988 by the United Nations Environment Programme ( UNEP ) and the UN 's World Meteorological Organization ( WMO ) '' ... to assess scientific , technical and socio-economic information relevant for the understanding of climate change , its potential impacts and options for adaptation and mitigation . '' -LSB- IPCC website -RSB- The Third Assessment Report ( TAR ) is the third of a series of assessments ; it has been superseded by the IPCC Fourth Assessment Report ( AR4 ) , released in 2007 .   Statements of the IPCC or information from the TAR are often used as a reference showing a scientific consensus on the subject of global warming , although a small minority of scientists take issue with the UN assessments ( see also Global warming controversy and Politics of global warming ) .

negative: Cold wave A cold wave ( known in some regions as a cold snap ) is a weather phenomenon that is distinguished by a cooling of the air . Specifically , as used by the U.S. National Weather Service , a cold wave is a rapid fall in temperature within a 24-hour period requiring substantially increased protection to agriculture , industry , commerce , and social activities . The precise criterion for a cold wave is determined by the rate at which the temperature falls , and the minimum to which it falls . This minimum temperature is dependent on the geographical region and time of year .   In the United States , a cold spell is defined as the national average high temperature dropping below 20 F.

negative: Solar gain Solar gain ( also known as solar heat gain or passive solar gain ) refers to the increase in temperature ( heat gain ) in a space , object or structure that results from solar radiation . The amount of solar gain increases with the strength of the sunlight , and with the ability of any intervening material to transmit or resist the radiation .   Objects struck by sunlight absorb the short-wave radiation from the light and reradiate the heat at longer infrared wavelengths . Certain materials and substances , such as glass , are more transparent to the shorter wavelengths than the longer ; when the sun shines through such materials , the net result is an increase in temperature -- solar gain . This effect , the greenhouse effect , so called due to the solar gain that is experienced behind the glass of a greenhouse , has since become well known in the context of global warming .

negative: Spring 2011 United Kingdom heat wave The Spring of 2011 in the United Kingdom was exceptional for the warm weather which occurred during April and the dry weather which was persistent during March and April in certain parts of the UK . April was statistically the warmest and driest in the country since records began in 1910 . There was a contrast between north-western parts of the UK which received substantial amounts of rainfall and south-eastern parts which received very little . As lack of rainfall continued in many parts during May , concerns arose that the country could submit to drought .   High pressure was the cause for the warm , dry weather experienced during April . A high temperature of 27.8 ° C was recorded on 23 April at Wisley , Surrey , the highest temperature recorded in April in the UK since 1949 . Thus , the Central England Temperature for the month was 3.7 ° C above the 1971-2000 average , and daily maximum temperatures were up to 6 ° C higher than average .

negative: Sea surface temperature Sea surface temperature ( SST ) is the water temperature close to the ocean 's surface . The exact meaning of surface varies according to the measurement method used , but it is between 1 mm and 20 m below the sea surface . Air masses in the Earth 's atmosphere are highly modified by sea surface temperatures within a short distance of the shore . Localized areas of heavy snow can form in bands downwind of warm water bodies within an otherwise cold air mass . Warm sea surface temperatures are known to be a cause of tropical cyclogenesis over the Earth 's oceans . Tropical cyclones can also cause a cool wake , due to turbulent mixing of the upper 30 m of the ocean . SST changes diurnally , like the air above it , but to a lesser degree . There is less SST variation on breezy days than on calm days . In addition , ocean currents such as the Atlantic Multidecadal Oscillation ( AMO ) , can effect SST 's on multi-decadal time scales , a major impact results from the global thermohaline circulation , which affects average SST significantly throughout most of the world 's oceans .   Coastal SSTs can cause offshore winds to generate upwelling , which can significantly cool or warm nearby landmasses , but shallower waters over a continental shelf are often warmer . Onshore winds can cause a considerable warm-up even in areas where upwelling is fairly constant , such as the northwest coast of South America . Its values are important within numerical weather prediction as the SST influences the atmosphere above , such as in the formation of sea breezes and sea fog . It is also used to calibrate measurements from weather satellites .

negative: Climate risk Climate risk means a risk resulting from climate change and affecting natural and human systems and regions .   In the course of increasing global temperature and extreme weather phenomena  the Intergovernmental Panel on Climate Change ( IPCC ) has been founded by the United Nations Environment Programme ( UNEP ) and the World Meteorological Organization ( WMO ) for a better understanding of climate change and meeting concerns of these observations . Its main aim is evaluating climate risks and exploring strategies for the prevention of these risks .

negative: Special Report on Global Warming of 1.5 °C The Special Report on Global Warming of 1.5 °C (SR15) was published by the Intergovernmental Panel on Climate Change (IPCC) on 8 October 2018. The report, approved in Incheon, South Korea, includes over 6,000 scientific references, and was prepared by 91 authors from 40 countries. In December 2015, the 2015 United Nations Climate Change Conference called for the report. The report was delivered at the United Nations' 48th session of the IPCC to "deliver the authoritative, scientific guide for governments" to deal with climate change.Its key finding is that meeting a 1.5 °C (2.7 °F) target is possible but would require "deep emissions reductions" and "rapid, far-reaching and unprecedented changes in all aspects of society." Furthermore, the report finds that "limiting global warming to 1.5 °C compared with 2 °C would reduce challenging impacts on ecosystems, human health and well-being" and that a 2 °C temperature increase would exacerbate extreme weather, rising sea levels and diminishing Arctic sea ice, coral bleaching, and loss of ecosystems, among other impacts. SR15 also has modelling that shows that, for global warming to be limited to 1.5 °C, "Global net human-caused emissions of carbon dioxide (CO2) would need to fall by about 45 percent from 2010 levels by 2030, reaching 'net zero' around 2050." The reduction of emissions by 2030 and its associated changes and challenges, including rapid decarbonisation, was a key focus on much of the reporting which was repeated through the world.

negative: 2002 India heat wave More than 1,030 people were killed in the 2002 heatwave in south India . Most of the dead were poor and elderly and a majority of deaths occurred in the southern state of Andhra Pradesh . In districts that were impacted most , the heat was so severe that ponds and rivers evaporated and in those same districts birds had fallen from the sky and animals were collapsing from the intense heat . It is said by officials to be the worst heat wave in four years . The relief commissioner of Andhra Pradesh , Rosaiah , said that the maximum number of 172 deaths related to heat took place in the East Godavari district . There were also 166 deaths in Prakasam and 144 deaths in West Godavari . Unusually high temperatures were detected across India during April of the year 2002 . In addition , this heat wave over northern zones of India lasted from the middle of April to the third week in May , thus , causing these fatalities . On May 10 the highest temperature recorded in the region of Gannavaram ( Vijayawada ) was 49 degrees Celsius ( 120.2 degrees Fahrenheit ) . According to the BBC News , `` Heatwaves are defined as periods of abnormally high temperatures and usually occur between March and June in India . May is the country 's hottest month , with an average maximum temperature of 41C ( 104F ) in Delhi . Longer , more severe heatwaves are becoming increasingly frequent globally . Intense heat can cause cramps , exhaustion and heat stroke . Thousands of people have died across India during heatwaves in 2002 and 2003 . '' The heatwaves also affected the northern states of Punjab , Haryana , Orissa and 100 people suffered from heat-related sickness .  2010 Indian heatwave

negative: David Parker (climatologist) David Parker is head of climate monitoring at the Hadley Centre , Exeter , England .   He has published extensively on the land and marine temperature record and its consistency . In 2002 , he was an organiser of a `` Workshop on Advances in the Use of Historical Marine Climate Data '' .   In 2004 , he has published a paper in Nature , showing that the urban heat island effect has not affected the historical temperature record . In this article , Parker shares his observations of the minimum temperature over 24 hours worldwide since 1950 that were expressed as anomalies . Also it includes his reasoning to why urbanization has not systematically exaggerated the observed global warming trends in minimum temperature . He further goes on to mention how the criterion for `` calm '' was changed while the global trend for minimum temperature remained unchanged . From his analysis he finds that windy and calm nights warmed at the same rate . Both the windy and calm increased at a rate of ( 0.16 + 0.03 C ) . He compares his small sample of 26 stations in North America and Siberia with global trends from 1950 to 1953 , covering over 5,000 stations . Estimates of recent global warming , supported by Parker 's analysis shows that urban warming has not introduced significant biases . `` The reality and magnitude of global-scale warming is supported by the near-equality of temperature trends on windy nights with trends based on all data . '' ( Parker ) This paper has been commented on by Roger Pielke , Sr. , et al. .

negative: Climate change in Argentina According to scientists , global warming is predicted to have significant effects on the climate of Argentina . Though temperatures have increased at a slower rate than the global average , nonetheless these impacts have occurred in many areas . If these trends continue , it is predicted that climate change will exacerbate existing natural disasters such as increasing the intensity and frequency of floods or create new ones .

negative: Global warming in Antarctica The effects of global warming in Antarctica may include rising temperatures and increasing snow melt .

negative: Global warming controversy The global warming controversy concerns the public debate over whether global warming is occurring , how much has occurred in modern times , what has caused it , what its effects will be , whether any action should be taken to curb it , and if so what that action should be . In the scientific literature , there is a strong consensus that global surface temperatures have increased in recent decades and that the trend is caused by human-induced emissions of greenhouse gases . No scientific body of national or international standing disagrees with this view , though a few organizations with members in extractive industries hold non-committal positions . Disputes over the key scientific facts of global warming are more prevalent in the media than in the scientific literature , where such issues are treated as resolved , and such disputes are more prevalent in the United States than globally .   Political and popular debate concerning the existence and cause of climate change includes the reasons for the increase seen in the instrumental temperature record , whether the warming trend exceeds normal climatic variations , and whether human activities have contributed significantly to it . Scientists have resolved these questions decisively in favour of the view that the current warming trend exists and is ongoing , that human activity is the cause , and that it is without precedent in at least 2000 years . Public disputes that also reflect scientific debate include estimates of how responsive the climate system might be to any given level of greenhouse gases ( climate sensitivity ) , how global climate change will play out at local and regional scales , and what the consequences of global warming will be .   Global warming remains an issue of widespread political debate , often split along party political lines , especially in the United States . Many of the issues that are settled within the scientific community , such as human responsibility for global warming , remain the subject of politically or economically motivated attempts to downplay , dismiss or deny them -- an ideological phenomenon categorised by academics and scientists as climate change denial . The sources of funding for those involved with climate science -- both supporting and opposing mainstream scientific positions -- have been questioned by both sides . There are debates about the best policy responses to the science , their cost-effectiveness and their urgency . Climate scientists , especially in the United States , have reported official and oil-industry pressure to censor or suppress their work and hide scientific data , with directives not to discuss the subject in public communications . Legal cases regarding global warming , its effects , and measures to reduce it have reached American courts . The fossil fuels lobby has been identified as overtly or covertly supporting efforts to undermine or discredit the scientific consensus on global warming .

negative: Scientific opinion on climate change The scientific opinion on climate change is the overall judgment among scientists regarding the extent to which global warming is occurring , its causes , and its probable consequences . The scientific consensus is that the Earth 's climate system is unequivocally warming , and that it is extremely likely ( meaning 95 % probability or higher ) that this warming is predominantly caused by humans . It is likely that this mainly arises from increased concentrations of greenhouse gases in the atmosphere , such as from deforestation and the burning of fossil fuels , partially offset by human caused increases in aerosols ; natural changes had little effect .   This scientific opinion is expressed in synthesis reports , by scientific bodies of national or international standing , and by surveys of opinion among climate scientists . Individual scientists , universities , and laboratories contribute to the overall scientific opinion via their peer-reviewed publications , and the areas of collective agreement and relative certainty are summarised in these respected reports and surveys .   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 IPCC Fourth Assessment Report stated that :  Warming of the climate system is unequivocal , as evidenced by increases in global average air and ocean temperatures , the widespread melting of snow and ice , and rising global average sea level .  Most of the global warming since the mid-20th century is very likely due to human activities .  Benefits and costs of climate change for -LSB- human -RSB- society will vary widely by location and scale . Some of the effects in temperate and polar regions will be positive and others elsewhere will be negative . Overall , net effects are more likely to be strongly negative with larger or more rapid warming .  The range of published evidence indicates that the net damage costs of climate change are likely to be significant and to increase over time .  The resilience of many ecosystems is likely to be exceeded this century by an unprecedented combination of climate change , associated disturbances ( e.g. flooding , drought , wildfire , insects , ocean acidification ) and other global change drivers ( e.g. land-use change , pollution , fragmentation of natural systems , over-exploitation of resources ) .   Some scientific bodies have recommended specific policies to governments , and science can play a role in informing an effective response to climate change . Policy decisions , however , may require value judgements and so are not included in the scientific opinion .   No scientific body of national or international standing maintains a formal opinion dissenting from any of these main points . The last national or international scientific body to drop dissent was the American Association of Petroleum Geologists , which in 2007 updated its statement to its current non-committal position . Some other organizations , primarily those focusing on geology , also hold non-committal positions .

negative: Global warming Global warming , also referred to as climate change , is the observed century-scale rise in the average temperature of the Earth 's climate system and its related effects . Multiple lines of scientific evidence show that the climate system is warming . Many of the observed changes since the 1950s are unprecedented in the instrumental temperature record which extends back to the mid 19th century , and in paleoclimate proxy records over thousands of years .   In 2013 , the Intergovernmental Panel on Climate Change ( IPCC ) Fifth Assessment Report concluded that `` It is extremely likely that human influence has been the dominant cause of the observed warming since the mid-20th century . '' The largest human influence has been emission of greenhouse gases such as carbon dioxide , methane and nitrous oxide . Climate model projections summarized in the report indicated that during the 21st century the global surface temperature is likely to rise a further 0.3 to for their lowest emissions scenario and 2.6 to for the highest emissions scenario . These findings have been recognized by the national science academies of the major industrialized nations and are not disputed by any scientific body of national or international standing .   Future climate change and associated impacts will differ from region to region around the globe . Anticipated effects include warming global temperature , rising sea levels , changing precipitation , and expansion of deserts in the subtropics . Warming is expected to be greater over land than over the oceans and greatest in the Arctic , with the continuing retreat of glaciers , permafrost and sea ice . Other likely changes include more frequent extreme weather events including heat waves , droughts , heavy rainfall with floods and heavy snowfall ; ocean acidification ; and species extinctions due to shifting temperature regimes . Effects significant to humans include the threat to food security from decreasing crop yields and the abandonment of populated areas due to rising sea levels . Because the climate system has a large `` inertia '' and greenhouse gases will stay in the atmosphere for a long time , many of these effects will not only exist for decades or centuries , but will persist for tens of thousands of years .   Possible societal responses to global warming include mitigation by emissions reduction , adaptation to its effects , building systems resilient to its effects , and possible future climate engineering . Most countries are parties to the United Nations Framework Convention on Climate Change ( UNFCCC ) ,  whose ultimate objective is to prevent dangerous anthropogenic climate change . Parties to the UNFCCC have agreed that deep cuts in emissions are required and that global warming should be limited to well below 2.0 C-change relative to pre-industrial levels , with efforts made to limit warming to 1.5 C-change .   Public reactions to global warming and concern about its effects are also increasing . A global 2015 Pew Research Center report showed a median of 54 % consider it `` a very serious problem '' . There are significant regional differences , with Americans and Chinese ( whose economies are responsible for the greatest annual CO2 emissions ) among the least concerned .

negative: Human Rights and Climate Change Human Rights and Climate Change is a conceptual and legal framework under which international human rights and their relationship to global warming are studied , analyzed , and addressed . The framework has been employed by governments , United Nations organs , intergovernmental and non-governmental organizations , human rights and environmental advocates , and academics to guide national and international policy on climate change under the United Nations Framework Convention on Climate Change ( UNFCCC ) and the core international human rights instruments .   Human rights and climate change analysis focuses on the anticipated consequences to humans associated with global environmental phenomena including sea level rise , desertification , temperature increases , extreme weather events , and changes in precipitation , as well as adaptation and mitigation measures taken by governments in response to those phenomena that may involve human rights or related legal protections .

negative: Cloud feedback Cloud feedback is the coupling between cloudiness and surface air temperature where a surface air temperature change leads to a change in clouds , which could then amplify or diminish the initial temperature perturbation . Cloud feedbacks can affect the magnitude of internally generated climate variability or they can affect the magnitude of climate change resulting from external radiative forcings .   Global warming is expected to change the distribution and type of clouds . Seen from below , clouds emit infrared radiation back to the surface , and so exert a warming effect ; seen from above , clouds reflect sunlight and emit infrared radiation to space , and so exert a cooling effect . Cloud representations vary among global climate models , and small changes in cloud cover have a large impact on the climate . Differences in planetary boundary layer cloud modeling schemes can lead to large differences in derived values of climate sensitivity . A model that decreases boundary layer clouds in response to global warming has a climate sensitivity twice that of a model that does not include this feedback . However , satellite data show that cloud optical thickness actually increases with increasing temperature . Whether the net effect is warming or cooling depends on details such as the type and altitude of the cloud ; details that are difficult to represent in climate models .