By the middle of this century, experts estimate that climate change is likely to displace between 150 and 300 million people. If this group formed a country, it would be the fourth-largest in the world, with a population nearly as large as that of the United States. Yet neither individual countries nor the global community are completely prepared to support a whole new class of “climate migrants.” The scale of this challenge is unlike anything humanity has ever faced. By midcentury, climate change is likely to uproot far more people than the Second World War, which displaced some 60 million across Europe, or the Partition of India, which affected approximately 15 million. The migration crisis that has gripped Europe since 2015 has involved something over one million refugees and migrants. It is daunting to envision much larger flows of people, but that is why the global community should start doing so now.

Donald Trump announced his presidential candidacy in June 2015 with a bold, double-edged promise: that he would build a “great wall” on the border separating the United States and Mexico, and that he would make Mexico pay for it. That polarizing statement, since repeated ad nauseam by commentators on both sides of the political spectrum, quickly went on to become one of the defining hallmarks of Trump’s presidential campaign. According to three political scientists from the University of California, Riverside, Trump’s remarks also galvanized his voter base in the initial stages of his campaign, particularly in areas that had experienced considerable Latino population growth in recent years.

DHS has installed experimental face-recognition system in nine U.S. airports. If DHS’s current plans are executed, every traveler flying overseas, American and foreign national alike, will soon be subject to a face recognition scan as part of this “biometric exit” program. A new report notes that neither Congress nor DHS has ever justified the need for the program. Congress never provided a rationale for it. Congress never provided a rationale for it while DHS has repeatedly questioned “the additional value biometric air exit would provide.” The biometric exit program also stands on shaky legal ground, and to make matters worse, the face scanning technology used by DHS may make frequent mistakes. “The privacy concerns implicated by biometric exit are at least as troubling as the system’s legal and technical problems,” the report notes.

New research predicts that migrants applying for asylum in the European Union will nearly triple over the average of the last fifteen years by 2100 if carbon emissions continue on their current path. The study suggests that cutting emissions could partially stem the tide, but even under an optimistic scenario, Europe could see asylum applications rise by at least a quarter.

Long before President Donald Trump promised to build a wall, Homeland Security used its powers of eminent domain to seize hundreds of acres of land in south Texas to construct a border fence. Under the law, if the government takes or damages your property, it’s supposed to pay to make you whole again. In Texas, the agency has paid $18 million to landholders over the last decade. But scores of Texas landowners who have lived in the shadow of the border fence for years were never compensated for any damage to their property values.

Subterranean warfare—whether involving human-made tunnels, underground urban infrastructure, or natural cave networks—has been an element of U.S. military operations from the Second World War and Vietnam to Iraq and Afghanistan. As above-ground commercial and military intelligence, surveillance, and reconnaissance (ISR) capabilities continue to grow more capable and ubiquitous, adversaries are increasingly heading underground to circumvent detection. Rapid global urbanization, furthermore, is accelerating the frequency and complexity of dangerous subterranean environments faced not just by warfighters, but also by emergency responders performing search-and-rescue missions underground: in collapsed mines, for instance, or municipal or urban settings wrecked by natural disaster. DARPA issues a Request for Information which seeks concepts for novel systems and component technologies to disruptively augment military and civilian operations underground.

From 1975 through 31 October 2017, the annual chance of being murdered in a terror attack on U.S. soil committed by a foreign-born person stands at 1 in 3,808,094 per year. In all, 3,037 people have been murdered on U.S. soil by 182 foreign-born terrorists from 1975 through 31 October 2017 (this figure includes the nearly 3,000 killed on 9/11). Of those 182 foreign-born terrorists, 63 initially entered with green cards. Including Tuesday’s attack, those who entered on a green card killed 16 people, or about 0.53 percent of all people murdered in terror attacks on U.S. soil committed by a foreigner. If the number of injuries in Tuesday’s attack stays at 12, terrorists who entered on green cards have injured about 203 people during this period in attacks.

The Israel military (IDF) on Monday morning destroyed a tunnel Hamas fighters were building under the Israel-Gaza Strip. The Hamas Health Ministry in Gaza said that nine Palestinians were killed and eight others were wounded when the IDF blew up the tunnel. Israel this summer began work on an underground barrier meant to counter attack tunnels.

Leaders of the populist, nationalist AfD party, which entered the Bundestag for the first time after Sunday federal election, have pledged to fight an “invasion of foreigners” with its new MPs. Alexander Gauland, speaking in Berlin the morning after the election results came in, said his party would “uncompromisingly address” immigration, an issue the party has campaigned on since late 2015. “One million people – foreigners – being brought into this country are taking away a piece of this country and we as AfD don’t want that,” Gauland told a press conference late Sunday. “We say we don’t want to lose Germany to an invasion of foreigners from a different culture. Very simple.”