T. Holt

The Direct Impact of Climate Change on Regional Labor Productivity

ABSTRACT Global climate change will increase outdoor and indoor heat loads, and may impair health and productivity for millions of working people. This study applies physiological evidence about effects of heat, climate guidelines for safe work environments, climate modeling, and global distributions of working populations to estimate the impact of 2 climate scenarios on future labor productivity. In most regions, climate change will decrease labor productivity, under the simple assumption of no specific adaptation. By the 2080s, the greatest absolute losses of population-based labor work capacity (in the range 11% to 27%) are seen under the A2 scenario in Southeast Asia, Andean and Central America, and the Caribbean. Increased occupational heat exposure due to climate change may significantly impact on labor productivity and costs unless preventive measures are implemented. Workers may need to work longer hours, or more workers may be required, to achieve the same output and there will be economic costs of lost production and/or occupational health interventions against heat exposures.

Generating Rainfall and Temperature Scenarios at Multiple Sites: Examples from the Mediterranean

A statistical downscaling methodology was implemented to generate daily time series of temperature and rainfall for point locations within a catchment, based on the output from general circulation models. The rainfall scenarios were constructed by a two-stage process. First, for a single station, a conditional first-order Markov chain was used to generate wet and dry day successions. Then, the multisite scenarios were constructed by sampling from a benchmark file containing a daily time series of multiple-site observations, classified by season, circulation weather type, and whether the day is wet or dry at the reference station. The temperature scenarios were constructed using deterministic transfer functions initialized by free atmosphere variables. The relationship between the temperature and rainfall scenarios is established in two ways. First, sea level pressure fields define the circulation weather types underpinning the rainfall scenarios and are used to construct predictor variables in the temperature scenarios. Second, separate temperature transfer functions are developed for wet and dry days. The methods were evaluated in two Mediterranean catchments. The rainfall scenarios were always too dry, despite the application of Monte Carlo techniques in an attempt to overcome the problem. The temperature scenarios were generally too cool. The scenarios were used to explore the occurrence of extreme events, and the changes predicted in response to climate change, taking the example of temperature. The nonlinear relationship between changes in the mean and changes at the extremes was clearly demonstrated.

A classification of ambient climatic conditions during extreme surge events off Western Europe

Principal factor analysis (PFA) of gridded daily mean sea level pressure and 500 hPa height data is used to create a classification of the large-scale ambient climatic conditions associated with severe storm surges in the Irish Sea and the North Sea. The original 100 pressure and 500 hPa height nodes are reduced to seven and four rotated factors, respectively. Each factor represents a single pressure or 500 hPa height system that can readily be combined with others to create complex climate scenarios. Using this property, the factor scores are tested against the dates of 23 known severe surges in the North and Irish Seas and important associated combinations of pressure system identified. A 100 years of data is searched for similar combinations and the results analysed. For the Irish Sea and the North Sea, the 1960s and 1970s indicate levels of surge activity unprecedented since the 1900s. This is followed by a sharp decline in the 1980s. taking the number of surges back to the levels of decades before the 1960s. The ambient pressure conditions for surges in the Irish Sea became more complex during the 1950s, and for the North Sea during the 1940s. This tendency persists to the present and could be a manifestation of shifts in storm tracks. Evidence from independent studies is provided to show that these changes are part of natural variability on decadal time scales rather than a long-term climatic change due to anthropogenic influences. Irish Sea and North Sea surges are associated with ambient conditions dominated by different pressure factors for each sea and with different steering mechanisms aloft.

Cryospheric Impacts of Soviet River Diversion Schemes

Soviet plans to divert water from rivers flowing into the Arctic Ocean have led to research into the impact of a reduction in discharge on Arctic sea ice. We consider the mechanisms by which discharge reductions might affect sea-ice cover and then test various hypotheses related to these mechanisms. We find several large areas over which sea-ice concentration correlates significantly with variations in river discharge, support,--__ ing two particular hypotheses. The first hypothesis concerns the area where the initial impacts are likely to which is the Kara Sea. Reduced riverflow is associated occur, with decreased sea-ice concentration in October, at the time of ice formation. This is believed to be the result of decreased freshening of the surface layer. the ice cover could have widespread climatic repercussions. We attempt to evaluate this risk by testing some of the theories discussed by Micklin (1981) concerning the cryospheric impact of reductions in riverflow. Sea-ice concentration data for the Arctic and its marginal seas are correlated with flow data for major Siberian rivers. The mechanisms examined are summarized in Table I and described in detail in the next section.

Climate change and the occurrence of extremes: some implications for the Mediterranean Basin

Intuitively we would expect climate change associated with increased emissions of greenhouse gases (so-called global wanning) to be linked to substantial impacts in the Mediterranean. This region is vulnerable to present- day fluctuations in the weather, especially with respect to water supply for competing activities such as agriculture and tourism. The climate models used in the Third Assessment Report of IPCC Working Group I indicate substantial drying in the Mediterranean associated with future climate change, which can only exacerbate the current situation.