Query: “Even if we meet the Paris goals of two degrees warming, cities like Karachi and Kolkata will become close to uninhabitable, annually encountering deadly heat waves like those that crippled them in 2015.

Relevant passages:
Karachi <=SEP=> Karachi ( -LSB- ; ڪراچي ALA-LC : , -LSB- kəˈrɑːˌtʃi -RSB- ) - the capital of the province of Sindh - is the largest and most populous city in Pakistan , as well as the 10th largest in the world and the world 's second most populous city proper . Ranked as a beta world city , the city is Pakistan 's premier industrial and financial centre . Karachi is also Pakistan 's most cosmopolitan city . Located on the shores of the Arabian Sea , Karachi is a major transportation hub , home to two of Pakistan 's largest seaports , the Port of Karachi and Port Bin Qasim , as well as the busiest airport in Pakistan .   Though the surroundings of Karachi have been inhabited for millennia , the city itself was founded as a village named Kolachi which was established as a fortified settlement in 1729 . The settlement increased in importance drastically with the arrival of British colonialists , who not only embarked on major works to transform the city into a major seaport , but also connected it with their extensive railway network . By the time of the Partition of India , the city was the largest in Sindh with an estimated population of 400,000 . Immediately following the independence of Pakistan , the city 's population increased dramatically with the arrival of thousands of Muslim immigrants from India , with Karachi remaining the primary destination of Indian Muslim migrants throughout the 1950s and 1960s . The city experienced rapid economic growth following independence , attracting migrants from throughout Pakistan and South Asia .   Karachi is one of Pakistan 's most secular and socially liberal cities . It is also the most linguistically , ethnically , and religiously diverse city in Pakistan . With an estimated population of between 15 and 23.5 million people in its greater metropolitan region , Karachi is considered to be the largest city in the Muslim world , and is the world 's 7th most populous urban agglomeration . Karachi is one of the world 's fastest growing cities , and has communities representing almost every ethnic group in Pakistan . Karachi is home to over 2 million Bangladeshi immigrants , 1 million Afghan refugees , and 400,000 Rohingyas from Myanmar .   Karachi is now Pakistan 's premier industrial and financial centre . The city has a formal economy estimated to be worth $ 113 billion . Karachi collects over a third of Pakistan 's tax revenue , and generates approximately 20 % of Pakistan 's GDP . Approximately 30 % of Pakistani industrial output is from Karachi , while Karachi 's ports handle approximately 95 % of Pakistan 's foreign trade . Approximately 90 % of the multinational corporations operating in Pakistan are headquartered in Karachi . Up to 70 % of Karachi 's workforce is employed in the informal economy , which is typically not included in GDP calculations .   Known as the `` City of Lights '' in the 1960s and 1970s for its vibrant nightlife , Karachi was beset by sharp ethnic , sectarian , and political conflict in the 1980s with the arrival of weaponry during the Soviet-Afghan war . The city had become well known for its high rates of violent crime , but recorded crimes sharply decreased following a controversial crackdown operation against criminals , the MQM political party , and Islamist militants initiated in 2013 by the Pakistan Rangers . The city 's murder rate in 2015 had decreased by 75 % compared to 2013 , and kidnappings decreased by 90 % , with the improved security environment triggering sharp increases in real-estate prices .

Climate change mitigation <=SEP=> Climate change mitigation consists of actions to limit the magnitude or rate of long-term climate change . Climate change mitigation generally involves reductions in human ( anthropogenic ) emissions of greenhouse gases ( GHGs ) . Mitigation may also be achieved by increasing the capacity of carbon sinks , e.g. , through reforestation . Mitigation policies can substantially reduce the risks associated with human-induced global warming .   According to the IPCC 's 2014 assessment report , `` Mitigation is a public good ; climate change is a case of the ` tragedy of the commons . Effective climate change mitigation will not be achieved if each agent ( individual , institution or country ) acts independently in its own selfish interest ( see international cooperation and emissions trading ) , suggesting the need for collective action . Some adaptation actions , on the other hand , have characteristics of a private good as benefits of actions may accrue more directly to the individuals , regions , or countries that undertake them , at least in the short term . Nevertheless , financing such adaptive activities remains an issue , particularly for poor individuals and countries . ''   Examples of mitigation include phasing out fossil fuels by switching to low-carbon energy sources , such as renewable and nuclear energy , and expanding forests and other `` sinks '' to remove greater amounts of carbon dioxide from the atmosphere . Energy efficiency may also play a role , for example , through improving the insulation of buildings . Another approach to climate change mitigation is climate engineering .   Most countries are parties to the United Nations Framework Convention on Climate Change ( UNFCCC ) . The ultimate objective of the UNFCCC is to stabilize atmospheric concentrations of GHGs at a level that would prevent dangerous human interference of the climate system . Scientific analysis can provide information on the impacts of climate change , but deciding which impacts are dangerous requires value judgments .   In 2010 , Parties to the UNFCCC agreed that future global warming should be limited to below 2.0 ° C ( 3.6 ° F ) relative to the pre-industrial level . With the Paris Agreement of 2015 this was confirmed , but was revised with a new target laying down `` parties will do the best '' to achieve warming below 1.5 ° C . The current trajectory of global greenhouse gas emissions does not appear to be consistent with limiting global warming to below 1.5 or 2 ° C . Other mitigation policies have been proposed , some of which are more stringent or modest than the 2 ° C limit .

Paris Agreement <=SEP=> The Paris Agreement ( Accord de Paris ) is an agreement within the United Nations Framework Convention on Climate Change ( UNFCCC ) dealing with greenhouse gas emissions mitigation , adaptation and finance starting in the year 2020 . The language of the agreement was negotiated by representatives of 195 countries at the 21st Conference of the Parties of the UNFCCC in Paris and adopted by consensus on 12 December 2015 . It was opened for signature on 22 April 2016 ( Earth Day ) at a ceremony in New York . As of May 2017 , 195 UNFCCC members have signed the treaty , 147 of which have ratified it . After several European Union states ratified the agreement in October 2016 , there were enough countries that had ratified the agreement that produce enough of the world 's greenhouse gases for the agreement to enter into force . The agreement went into effect on 4 November 2016 .   The head of the Paris Conference , France 's foreign minister Laurent Fabius , said this `` ambitious and balanced '' plan is a `` historic turning point '' in the goal of reducing global warming .   One year on , the ratification of the Paris Agreement was celebrated by the Mayor of Paris Anne Hidalgo by illuminating the Eiffel Tower and the Arc de Triomphe , Paris ' most iconic monuments , in green .

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 .