Query: A recent study in Nature Geoscience, for instance, called into question whether the Arctic’s melting, and in particular its sea ice loss, has been causing winter cooling over Eurasia, another idea that has been swept up in the debate over the jet stream and weather extremes.”

Relevant passages:
Rossby wave <=SEP=> Rossby waves , also known as planetary waves , are a natural phenomenon in the atmosphere and oceans of planets that largely owe their properties to rotation of the planet . Rossby waves are a subset of inertial waves .   Atmospheric Rossby waves on Earth are giant meanders in high-altitude winds that have a major influence on weather . These waves are associated with pressure systems and the jet stream . Oceanic Rossby waves move along the thermocline : the boundary between the warm upper layer and the cold deeper part of the ocean .

Polar amplification <=SEP=> Polar amplification is the phenomenon that any change in the net radiation balance ( for example greenhouse intensification ) tends to produce a larger change in temperature near the poles than the planetary average . On a planet with an atmosphere that can restrict longwave radiation to space ( a greenhouse effect ) , surface temperatures will be warmer than a simple planetary equilibrium temperature calculation would predict . Where the atmosphere or an extensive ocean is able to convect heat polewards , the poles will be warmer and equatorial regions cooler than their local net radiation balances would predict .   In the extreme , the planet Venus is thought to have experienced a very large increase in greenhouse effect over its lifetime , so much so that its poles have warmed sufficiently to render its surface temperature effectively isothermal ( no difference between poles and equator ) . On Earth , water vapor and trace gasses provide a lesser greenhouse effect , and the atmosphere and extensive oceans provide efficient poleward heat transport . Both palaeoclimate changes and recent global warming changes have exhibited strong polar amplification , as described below .

Global warming <=SEP=> 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 .

Arctic sea ice decline <=SEP=> Arctic sea ice decline is the sea ice loss observed in recent decades in the Arctic Ocean . The Intergovernmental Panel on Climate Change ( IPCC ) Fourth Assessment Report states that greenhouse gas forcing is largely , but not wholly , responsible for the decline in Arctic sea ice extent . A study from 2011 suggested that internal variability enhanced the greenhouse gas forced sea ice decline over the last decades . A study from 2007 found the decline to be `` faster than forecasted '' by model simulations . The IPCC Fifth Assessment Report concluded with high confidence that sea ice continues to decrease in extent , and that there is robust evidence for the downward trend in Arctic summer sea ice extent since 1979 . It has been established that the region is at its warmest for at least 40,000 years and the Arctic-wide melt season has lengthened at a rate of 5 days per decade ( from 1979 to 2013 ) , dominated by a later autumn freezeup . Sea ice changes have been identified as a mechanism for polar amplification .