Climate change is defined as long-term alterations in weather outside historical ranges.
Climate can be influenced by both natural events and human activities. Natural events such as variations in the tilt of the earth towards the sun, solar output, the Earth’s orbital path around the sun and volcanic eruptions can influence Earth’s climate. Over the course of Earth’s history these factors have contributed to a natural cycling of global climate periods including cooler ice ages and warmer interglacial periods.
Human activities can also influence climate by altering the concentrations of atmospheric heat trapping compounds known as greenhouse gases. Greenhouse gases trap heat in the Earth’s surface preventing it from escaping into space much the same as a greenhouse traps heat. These activities can increase concentrations of carbon dioxide, methane, nitrous oxide and water vapour that trap heat energy in the lower atmosphere, increasing air temperatures and altering weather patterns.
As our water resources are highly dependent on climate parameters such as air and water temperatures, precipitation, evaporation, snow and ice cover, changes to these parameters will carry significant implications to overall water supplies and their management (see water cycle). For example greater variability in lake levels and streamflows can influence water supply quantity and quality and increases the potential of natural hazard events such as droughts, floods and erosion.
Water has often been termed the ‘life-blood’ of the environment. It sustains the human population and is vital for all natural ecosystems. Managing its variability in both quantity and quality has a pivotal impact on Ontario’s continued social and economic well being.
Recent evidence released by the Intergovernmental Panel on Climate Change (IPCC 2007) suggests that the rate of warming over the last hundred years is accelerating and that the Earth’s surface has warmed by 0.74 (±0.18oC). The IPCC also suggests most of this warming is due to human activities since World War II. Computer projections indicate that as greenhouse gas emissions continue to rise worldwide, earth’s climate will continue to warm throughout the 21st century. Ontarians will need to respond to these warming trends and the impacts it carries on the natural environment.
Climate change will affect how resource agencies such as the Ministry of Natural Resources (MNR) care for the province’s natural assets. MNR will continue to work with clients and partners better to understand climate change, help mitigate its impacts by reducing greenhouse gas emissions, and where possible, help Ontarians adapt.
To find out more about climate change visit: Go Green Ontario - About Climate Change.
