The so-called wave of refugees crossing the Mediterranean to reach Europe in 2015 put a spotlight on the readiness or lack of such to welcome them. Finding themselves on a treadmill, fighting hard to survive, many people are fearful that they become losers and perceive refugees as unwelcome competitors for goods already scarce in a hostile world. How can theories of justice illuminate and help resolve such a crisis? The article argues that all human beings have the same right to live on an ecologically viable earth; this principle holds regardless of when and where they happen to live. Joseph Carens' claim that justice requires open borders is discussed, showing up the limits of the influential theory of John Rawls. However, while we agree with Carens that those insisting on the restrictions of immigration carry the burden of argument, Carens must be criticized for failing to raise the question of why people leave their homes so as to cross borders in today's world, being forced to do so rather than freely choosing to.