Climate Change is NOT Being Nice to Mother Nature – Overview
This is the first part of a series of blog posts that summarize some of the negative effects of climate change on the world’s ecosystems.
“Observed recent changes in climate, especially warmer regional temperatures, have already had significant impacts on biodiversity and ecosystems, including causing changes in species distributions, population sizes, the timing of reproduction or migration events, and an increase in the frequency of pest and disease outbreaks. By the end of the century, climate change and its impacts may be the dominant direct driver of biodiversity loss and changes in ecosystem services globally. The balance of scientific evidence suggests that there will be a significant net harmful impact on ecosystem services worldwide if global mean surface temperature increases more than 2o Celsius above pre-industrial levels or at rates greater than 0.2o Celsius per decade” (Millennium Ecosystem Assessment, Reid et al., 2005)
An ecosystem is a dynamic complex of plant, animal and micro-organism communities, and the non-living environment, interacting as a functional unit. Ecosystems are critical in supporting the well-being of humans (IPCC, 2007; Millennium Ecosystem Assessment, Reid et al., 2005).
According to the IPCC (2007):
Ecosystems provide many goods and services that are of vital importance for the functioning of the biosphere, and provide the basis for the delivery of tangible benefits to human society. These services are separated into four categories.
- Supporting services, such as primary and secondary production, and biodiversity, a resource that is increasingly recognized to sustain many of the goods and services that humans enjoy from ecosystems. These provide a basis for three higher-level categories of services.
- Provisioning services, such as products, i.e., food (including game, roots, seeds, nuts and other fruit, spices, fodder), fibre (including wood, textiles) and medicinal and cosmetic products (including aromatic plants, pigments;)
- Regulating services, which are of paramount importance for human society such as (a) carbon sequestration, (b) climate and water regulation, (c) protection from natural hazards such as floods, avalanches or rock-fall, (d) water and air purification, and (e) disease and pest regulation.
- Cultural services, which satisfy human spiritual and aesthetic appreciation of ecosystems and their components.
The IPCC (2007) has determined that there are five key issues pertaining to assessing the vulnerability of ecosystems to anthropogenic climate change:
- Ecosystems can tolerate some future climate change but will they be able to adapt to significant future climate change?
- Climate change will increasingly exacerbate human-induced pressures (land use, nitrogen deposition, pollution and invasive species), causing a progressive decline in biodiversity.
- Will ecosystems exceed critical thresholds and trigger responses in the biosphere that could lead via positive feedback to novel states that are poorly understood?
- The understanding of time-lags in ecosystem responses is still developing. Many ecosystems may take several centuries (vegetation) or even possibly millennia (where soil formation is involved) before responses to a changed climate are played. A better understanding of transient responses and the functioning of ecosystems under continuously changing conditions is needed to narrow uncertainties about critical effects and to develop effective adaptation responses at the time-scale of interest to human society.
- Extinctions of species that are critical for ecosystem functioning are virtually certain to reduce societal options for adaptation responses.
As the figure above shows shows, climate change is causing very rapid increases in the impact on all ecosystems over the past century. Climate change impact on the biodiversity of polar regions is high while coastal, mountain, and dryland regions are being impacted moderately (Millennium Ecosystem Assessment, Reid et al., 2005).
The figure above (Gonzalez et al., 2010) maps areas of ecosystem vulnerability to climate change while the figure below (USGRP, 2009) shows the key impacts of climate change in the United States.
Next post: Climate change impacts on freshwater wetlands, lakes & rivers