Estimation of the economic impact of temperature changes induced by a shutdown of the thermohaline circulation: an application of FUND

The integrated assessment model FUND 2.8n is applied in an assessment to estimate the magnitude of the general market and non-market impacts of temperature changes caused by a possible shutdown of the thermohaline circulation (THC). The monetized impacts of this change in environmental conditions are determined for 207 individual countries for two scenarios: one warming scenario in which the THC weakens but remains intact, and another in which the THC breaks down. Eight different response patterns are identified. The dominant pattern is that a THC shutdown has an offsetting effect on the underlying warming trend. Depending on whether the impacts of warming are initially beneficial or detrimental, the economic effects of a THC shutdown show distinct regional variability. Key economic sectors affected are water resources and energy consumption, as well as cardiovascular and respiratory diseases among health impacts. The maximum national impact of a shutdown of the THC turns out to be of the magnitude of a few per cent of GDP, but the average global impact is much smaller. The results indicate that the temperature effect of a THC shutdown does not create an insurmountable economic threat on a global scale, but may cause severe damages to individual countries. However, a consideration of other climatic impacts such as precipitation and sea level changes is likely to alter the identified trends in economic development.

本研究采用综合评估模型FUND 2.8n，针对温盐环流（thermohaline circulation, THC）可能中断所引发的气温变化所产生的整体市场与非市场影响规模开展评估，针对两种情景下的207个国家量化了该环境条件变化带来的货币化影响：其一为温盐环流减弱但保持完整的增温情景，其二为温盐环流完全崩溃的情景。研究共识别出八种不同的响应模式，其中主导模式为温盐环流中断会抵消潜在的增温趋势；根据变暖影响最初呈现出的利弊属性，温盐环流中断所带来的经济影响表现出显著的区域异质性。受影响的核心经济部门包括水资源与能源消费领域，健康影响范畴则涵盖心血管疾病与呼吸系统疾病。研究结果显示，温盐环流中断对单个国家造成的最大影响规模约为国内生产总值（Gross Domestic Product, GDP）的数个百分点，但全球平均影响则要小得多。结果表明，温盐环流中断带来的气温效应并不会在全球尺度上构成难以逾越的经济威胁，但可能对部分国家造成严重损害。然而，若将降水、海平面变化等其他气候影响纳入考量，此前识别出的经济发展趋势或会发生改变。