and remained within the top 10 throughout the decade. Global warming became increasingly noticeable through new record temperatures in different years and extreme weather events on all continents. The CO2 concentration rose from 390 to 410 PPM over the decade. At the same time, combating pollution and climate change continued to be major concerns, as protests, initiatives, and legislation garnered substantial media attention. Particularly, the Paris Agreement (2015) was adopted, and the global climate youth movement was formed. Major natural disasters included the 2010 Haiti earthquake, the 2011 Tōhoku earthquake and tsunami, the Nepal earthquake of 2015, the 2018 Sulawesi earthquake and tsunami, and the devastating hurricanes Bopha (Pablo), Haiyan (Yolanda), and Maria, as well as the 2019 European heat waves. During the decade, the world population grew from 6.9 to 7.7 billion people. There were approximately 1.4 billion births during the decade (140 million per year), and about 560 million deaths (56 million per year). Politics and wars Major conflicts The prominent wars of the decade include: International wars Civil wars Revolutions and major protests Successful revolutions and otherwise major protests of the decade include, but are not limited to: Arab Spring The Arab Spring was a series of anti-government protests, uprisings, and armed rebellions that spread across much of the Islamic world in the early 2010s. It began in response to oppressive regimes and a low standard of living, starting with protests in Tunisia. In the news, social media has been heralded as the driving force behind the swift spread of revolution throughout the world, as new protests appear in response to success stories shared from those taking place in other countries. In many countries, the governments have also recognised the importance of social media for organising and have shut down certain sites or blocked Internet service entirely, especially in the times preceding a major rally. Governments have also scrutinised or suppressed discussion in those forums through accusing content creators of unrelated crimes or shutting down communication on specific sites or groups, such as through Facebook. Nuclear proliferation On 8 April 2010, the United States and Russia signed a treaty in Prague, Czech Republic agreed to reduce the stockpiles of their nuclear weapons by half. It is meant to replace the Strategic Offensive Reductions Treaty (SORT), which was set to expire. The treaty went into force on 5 February 2011 after it was ratified by both nations. In