Cambio climatico

1. Climate's changed before, is always changing. We have had ice ages and warmer periods. Ice ages have occurred in a hundred thousand year cycle for the last 700 thousand years, and there have beenprevious periods that appear to have been warmer than the present despite CO2 levels being lower than they are now.

Rising greenhouse gas levels are an external forcing, which has caused climatechanges many times in Earth's history. They're causing an energy imbalance and the planet is building up heat. From Earth's history, we know that positive feedbacks will amplify the greenhousewarming. So past climate change doesn't tell us that humans can't influence climate; on the contrary, it tells us that climate is highly sensitive to the greenhouse warming we're now causing.

2.Climate change is becoming increasingly apparent. Temperatures around the world have increased over these years and it was noticed that mean temperatures for most cities were above average and somecities experienced their warmest temperatures ever. This change has become of a great concern to many as these changes have an impact on ecosystems, habitats, wildlife, cultures, artifacts and the life ofhumans. Scientists predict that such changes will speed up in the future and more extreme weathers, public health risks and water shortage will be expected

The United States and Mexico arecooperating closely on steps to reduce carbon emissions in our countries. The Environmental Protection Agency has worked closely with the National Institute of Ecology to bring Mexico’s National Inventoryof Greenhouse Emissions up to date. Mexico has urged the setting up of a global “Green Fund,” which would receive contributions from all but the poorest countries in the world to financeenvironmentally friendly projects.

3. If the governments take the necessary steps, they wouldn’t worry. Only will severe desertification destroy many temperate and tropical ecosystems, it may also...