The thesis of these extracts from Bill McKibben's book, Earth: Making Life on a Tough New Planet, is that humanity has changed the Earth permanently due to global warming. . This idea is based on the assumption that global warming has caused irrevocable changes in the environment and that humans have only recently altered the Earth. One of the key premises on which these extracts are based is the idea that the changes caused by global warming are irreversible. McKibben argues that we have passed the point where even drastic changes in the way we live could not prevent global warming from worsening. Even if we did "everything possible to become light and efficient," research indicates that it is "'unlikely' that we would be able to stay below 650 parts per million [of carbon dioxide]," nearly twice the acceptable. amount (McKibben 2010, 13). The author also believes that changes due to global warming are permanent because we cannot recover what we lose. Rainforest, coral reefs and ice are disappearing and “Once such trends begin, we cannot slow them down. We don’t know how to refreeze the Arctic or regrow a rainforest” (McKibben 2010, 28). According to McKibben, the world has reached this point, at least in part, because we have already exceeded the acceptable amount of carbon dioxide in the atmosphere, which is 350 parts per million. We learned this too late according to McKibben, because by the time the research supporting this idea was presented, the planet's atmosphere already contained nearly 390 parts per million of carbon dioxide (McKibben 2010, 12). For the author, these irrevocable changes mean that "the land we have known – the only land we have ever known – has disappeared" (McKibben 2010: 18), which brings us to the heart of the text, the idea that civilization will be just as irreversibly destroyed. changed as the world. The text also assumes that the earth has been stable for most of human history. On a large scale, this is certainly true, considering that “the temperature has barely moved; on a global average, it oscillates in the narrowest range, between fifty-eight and sixty degrees Fahrenheit,” and this weather is predictable with only “storms and abnormal disturbances” (McKibben 2010, 4). This doesn't take into account the broad changes that humans have caused at more local levels. Changing our environment is a defining attribute of being human that should not be completely neglected. This avoidance of humanity's impact on Earth is partly because McKibben, rightly, views the issue of global warming from a very human perspective..