What would happen if humans stopped existing?

What would happen to Earth if humans went extinct. Tells Alan Weisman, it is just amazingly thrilling how fast nature can bury us. Would the world without us survive? What could drive humanity to extinction? “Without people to run pumps that divert rainfall and rising groundwater, the subways of huge sprawling cities like London and New York would flood within hours of our disappearance,” is one of the observations of Weisman’s studies. Oil refineries and nuclear plants would go unchecked. Mountains of solid waste, petroleum waste and organic pollutants will create havoc to the remaining wildlife. Ultimately they will be buried to continue the havoc. Underground water will corrode the metal structure base, resulting in the collapse of subterranean transport systems. In due course all pavements would crack, all bridges would collapse. In place of concrete jungles, there will be grasslands, shrubbery and dense stands of trees. There will be fire sparked by lightning. Metal and glass structures would be the first casualties; stone structures would be the last. Insects will be in gay abundance because of the non-availability of pesticides. Surrounding habitats will encourage more wildlife to move in and take up residence. There will be a corresponding increase in biodiversity. In the absence of hunters, the likes of lions, elephants, tigers, rhinoceroses and bears will be in abundance. Large animals would rule the world. Nature, however, will take millions of years to bring the changes of this magnitude. These will make an impact on climate change. Vast amounts of carbon dioxide will be dissolved in the oceans, enough to kill the marine species. Oceans will get converted into ‘bottomless carbon sinks’. As we leave, we shall leave climate change as a legacy. Hopefully, some marine species will thrive under extreme conditions, as they did during the Jurassic period. Hopefully, nature will find a way to resurge. Are there any lessons for us to learn from this imagined future? The purpose of writing the book, Weisman says, is "to see how beautifully nature could come back, and even heal a lot of the scars that we've placed on this planet."