Scottish Government

Global Atmosphere

Annual Mean Land Temperature: 1857-2004

The above table and chart show the mean annual temperature within a 5 degree grid box extending from 55-60 degrees North and 0-5 degrees West, which includes most of Scotland and parts of England.

The balance between incoming solar energy and outgoing infrared radiation determines the earth's temperature. Changes in the amount of energy retained within the atmosphere affects global climate, which naturally exhibits long-term fluctuations. Current climate trends are unlikely to be entirely natural in origin however, and there is now evidence that human activities are having a discernible impact on the global climate. ¹

Whilst the global impacts of climate change are considerable, there are also wide-ranging implications for Scotland. Flood risk, water resources, agriculture, tourism and health may be affected, all of economic, social and environmental importance.

Over the period 1901-2000, the change in mean global surface temperature explained by a linear trend is 0.57°C. Over the same period, the change for the grid covering Scotland shows a similar land temperature rise of 0.61°C. By 2100, temperatures in Scotland are predicted to rise by 3.5°C during the summer months and around 2.5°C during the winter months. ²

SOURCE: MET OFFICE, UNIVERSITY OF EAST ANGLIA (CLIMATE RESEARCH UNIT)

Global warming will have an effect on all weather patterns, and changes in the amount of rainfall are predicted. The UK Climate Impacts Programme climate scenarios ² indicate that rainfall patterns in Scotland will change to wetter winters and drier summers. It is estimated that winters will be over 30% wetter in some places, while summers will be up to 40% drier. Precipitation changes have several implications for Scotland, affecting water resources, flood and drought risk, and habitat loss.

The average annual precipitation in the 1980s and the 1990s was higher than in previous decades, particularly the 1970s, which contained several years with below average rainfall.

SOURCE: MET OFFICE ⁵

Emissions (million tonnes of carbon equivalent) ^R

It should be noted that improved data sources and estimation techniques have routinely led to revision of historic greenhouse gas emission estimates.

'Greenhouse' gases ( GHGs) in the atmosphere help to retain radiation, resulting in warming of the lower atmosphere and earth surface. The process, known as the greenhouse effect, is essential to maintain global temperatures that sustain life on earth. Atmospheric concentrations of GHGs have increased as a result of human activities since the industrial revolution ( c.1750). This has enhanced the greenhouse effect.

The Kyoto Protocol (1997) set legally binding targets under which the UK must reduce emissions of a 'basket' of six GHGs to 12.5% below baselines (1990 for carbon dioxide, methane and nitrous oxide, and 1995 levels for fluorinated compounds) by 2008-2012. Against these base years Scottish emissions in 2002 were 6% lower.

SOURCE: NETCEN¹²

Emissions (million tonnes CO ₂) ^R

It should be noted that improved data sources and estimation techniques have routinely led to revision of historic greenhouse gas emission estimates.

Carbon dioxide (CO ₂) is the main contributor to greenhouse gas emissions. The UK contributes 2% to total global CO ₂ emissions. ¹⁶ In 2002, CO ₂ made up 85% of all greenhouse gas emissions in the UK (weighted by global warming potential ⁷). Scotland emitted 60.9 million tonnes of CO ₂ in 2002 (around 11% of the UK total), a decline of 2 million tonnes from 1990 levels.

The energy industries are an important sector for CO ₂ emissions in Scotland, generating CO ₂ primarily from the combustion of fossil fuels. Emissions from the energy industries have increased by 11% since 1990.

Land use change and forestry also contributes to CO ₂ emissions in Scotland, releasing 20% of emissions in 2002 (land use change being the main contributor). Estimates of emissions for this sector are particularly uncertain since they depend critically on assumptions made on the rate or gain of carbon in the organic matter rich soils, which predominate in Scotland.

SOURCE: NETCEN ¹²

Column ozone concentrations (Dobson units)

The stratospheric ozone layer, located around 10-30km above the Earth's surface, forms a protective shield against harmful solar ( UVB) radiation. ¹⁷ Thinning of the ozone layer has occurred since the beginning of the 1980s in all regions except equatorial ones. Depletion is most marked in the Antarctic where, in 2003, the Antarctic ozone hole reached 29 million square kilometres in area (about 350 times the land area of Scotland). ¹⁶ Ozone depleting substances ( ODS) include chlorofluorocarbons ( CFCs), hydrochlorofluorocarbons and halons, which are used as refrigerants, solvents, foam blowing agents and aerosol propellants.

The 1987 Montreal Protocol set guidelines to eliminate the global production and use of ODS. European production of CFCs for non-essential use fell to zero in 1995. ¹⁶ However, leaks from old equipment and the long life of these substances in the lower atmosphere mean that full recovery of the ozone layer is not predicted until 2050.

Over the last 20 years, total ozone cover over Lerwick has fluctuated. Record low levels were observed in October 2004. This has been attributed to local meteorological conditions and the passage of Arctic lower stratospheric air in which ozone had been depleted.

SOURCE: MET. OFFICE, NETCEN