The majority of the world’s scientists agree that the Earth's climate is changing because of manufactured greenhouse gases. The result will be a substantially altered climate. ZeroCarbonCity tackles the issues that will affect this climate change.

WHAT ARE THE SIGNS?
The Earth's climate is changing. Here's some evidence, taken from historical records of the past 142 years.

			The global temperature has risen by about 0.6ºC since the beginning of the 20th century.
			About 0.4ºC of this warming has occurred since the 1970s.
			The warmest year in this period was 1998.
			The 1990s was the warmest decade of the last 100 years.

WHAT ARE THE PREDICTIONS?
Computer simulation models show that the global temperature (its mean average) is likely to rise anywhere between 1.5ºC and 5.9ºC by 2100. This estimate has a wide range because scientists are uncertain about how the climate will respond to increased concentrations of greenhouse gases. Also, we don't know how emissions of greenhouse gases will change in the coming decades; how much we emit will depend on our choices as a global society.

WHAT WILL THE EFFECTS BE?
One major effect of climate change will be the continuing rise in sea-levels. Global rainfall is likely to increase by about two percent per degree of warming, although some regions will become more dry. Changing rainfall patterns are likely to increase soil erosion and subsidence, and profoundly affect water availability and quality. Drier soils will change the type and yield of crops, increasing the risk of famine in some areas. Extreme storms and flooding will also become a serious threat. Health is likely to be affected directly (summer heat stress) and indirectly (food poisoning). Infectious diseases such as malaria are also expected to spread.

WHAT IS HAPPENING?
Countries throughout the globe are already committed to working with climate change over the next 100 years. Society needs to live with this change (adaptation), as well as reducing the change (mitigation). Campaigns such as ZeroCarbonCity will raise awareness of the issues and help to ensure that adaptation and mitigation continues. If you would like to know more about the causes of this climate change, we have a selection of online resources and books chosen by science writer, John Turney.