What is the difference between weather and climate?
Weather is the short-term (minutes to months) state of the atmosphere at a specific time and place. Popularly, weather is thought of in terms of temperature, humidity, precipitation, cloudiness, brightness, visibility, and wind. Climate is commonly defined as the weather averaged over a long period of time; where the standard averaging period is 30 years.
How are temperatures changing?
Instrumental observations over the past 157 years show that temperatures at the surface have risen globally, with important regional variations. For the global average, warming in the last century has occurred in two phases, from the 1910s to the 1940s (0.35°C), and more strongly from the 1970s to the present (0.55°C). An increasing rate of warming has taken place over the last 25 years, and 11 of the 12 warmest years on record have occurred in the past 12 years (IPCC, 2008). Confirmation of global warming comes from warming of the oceans, rising sea levels, glaciers melting, sea ice retreating in the Arctic and diminished snow cover in the Northern Hemisphere (IPCC, 2008).
How is rainfall changing?
Observations show that changes are occurring in the amount, intensity, frequency and type of precipitation. These aspects of precipitation generally exhibit large natural variability (IPCC, 2008). Pronounced long-term trends from 1900 to 2005 have been observed in precipitation amount in some places; significantly drier in southern Africa. Widespread increases in heavy precipitation events have been observed, even in places where total amounts have decreased. These changes are associated with increased water vapour in the atmosphere arising from the warming of the world's oceans, especially at lower latitudes. There are also increases in some regions in the occurrences of both droughts and floods (IPCC, 2008).
How reliable are the models used to make projections of future climate change?
Climate models are a mathematical representation of the climate system based on its physical, chemical and biological components (IPCC, 2008). There is considerable confidence that climate models provide credible quantitative estimates of future climate change. Confidence in climate models is higher for some climate variables, such as temperature, than for others, such as precipitation. One source of confidence comes from the ability of models to simulate important aspects of the current climate (IPCC, 2008).
How would decision-makers/stakeholders get access to and use the climate change information?
Capacity building workshops will be held with key area stakeholders across southern Africa identified in the stakeholder mapping exercise and in country meetings. During these workshops the following will be communicated:
- Climate variability information including the latest seasonal forecast produced through SARCOF
- Latest climate change projections (temperature and precipitation data)
- GIS workshops will help stakeholders interact with the data in a spatial manner
- Breakaway groups will help stakeholders understand the data and how to apply it to their area of work
What kind of climate change data will be made available through this project?
Monthly projections of temperature (minimum, maximum and mean), precipitation (number of days of rainfall per month, number of dry days per month and monthly rain totals). This information will be made available in the form of maps as well as shapefiles.
At what spatial scale will this climate change information be available?
The second versions of the downscaled global climate models have a finer resolution, meaning that they can be used in local planning. The data is projected at a scale of 25km².
What is global change?
Global change refers to changes in the environment that may alter the capacity of the earth to sustain life and human well-being over the long term. These changes may be occurring locally and be anthropogenic (human) or natural in their origin, but can often result in impact at various levels.
I am not an expert, scientist or Geographic Information Systems (GIS) analyst - are the workshops still useful for me?
Yes! This project is designed for all kinds of users, providing basic information and easy-to-read maps and articles for non-expert groups, as well as more detailed information that can be manipulated and analysed by GIS users, analysts and others.
Who are the target users?
Primary targets include regional and sub-regional stakeholders from a variety of sectors. There are countless other stakeholders who have expressed an interest in and can benefit from science and information made available through this project, including among others, national and provincial government, politicians, consultants, businesses, researchers and analysts, students, non-governmental organizations and others.
Where can I find out more information?