Appropriate experimental ecosystem warming methods by ecosystem, objective, and practicality

The temperature of the Earth is rising, and is highly likely to continue to do so for the foreseeable future. The study of the effects of sustained heating on the ecosystems of the world is necessary so that we might predict and respond to coming changes on both large and small spatial scales. To this end, ecosystem warming studies have been performed for more than 20 years using a variety of methods. These warming methods fall into two general categories: active and passive. Active warming methods include heat-resistance cables, infrared (IR) lamps and active field chambers. Passive warming methods include nighttime warming and passive field chambers. An extensive literature review was performed and all ecosystem warming study sites were compiled into a master list. These studies were divided by latitude and precipitation, as well as the method type used and response variables investigated. The goals of this study were to identify: (1) the most generally applicable, inexpensive and effective heating methods; and (2) areas of the world that are understudied or have been studied using only limited warming methods. It was found that the most generally applicable method, and the one that is most true to climate change predictions, is IR heating lamp installation. The least expensive method is passive chambers. The extreme lower and upper latitudes have been investigated least with ecosystem warming methods, and for the upper-mid-latitudes (60–80°) there have been limited studies published using methods other than passive chambers. Ecosystem warming method limitations and recommendations are discussed.