"In this report, we conclude that we will continue to adhere to the five basic homeland security missions set forth in the first Quadrennial Homeland Security Review report in 2010, but that these missions must be refined to reflect the evolving landscape of homeland security threats and hazards. The Deepwater Horizon oil spill in 2010, Hurricane Sandy in 2012, and the Boston Marathon bombing in 2013 illustrate these evolving threats and hazards. We must constantly learn from them and adapt. The terrorist threat is increasingly decentralized and may be harder to detect. Cyber threats are growing and pose ever-greater concern to our critical infrastructure systems as they become increasingly interdependent. Natural hazards are becoming more costly to address, with increasingly variable consequences due in part to drivers such as climate change and interdependent and aging infrastructure. Meanwhile, this Nation's homeland security architecture has matured over the past four years, and we are determined that this progress continue. For example, our law enforcement and intelligence communities are becoming increasingly adept at identifying and disrupting terrorist plotting in this country. Programs such as TSA [Transportation Security Administration] Pre�"™ and Global Entry demonstrate the effectiveness and efficiency of risk-based security that can be achieved within budget constraints. It is also worth noting that, in late 2013, DHS received its first unqualified or 'clean' audit opinion; this occurred just 10 years after the Department's formation, which was the largest realignment and consolidation of Federal Government agencies and functions since the creation of the Department of Defense in 1947."
U.S. Department of Homeland Security: http://www.dhs.gov/