Climate change scenario in the context of Climate change adaptation

There are several plausible pathways that could lead to plant and animal species extinction from climate change. Every species has evolved to exist within a certain ecological niche, but climate change leads to changes of temperature and average weather patterns. These changes can push climatic conditions outside of the species' niche, and ultimately render it extinct. Normally, species faced with changing conditions can either adapt in place through microevolution or move to another habitat with suitable conditions. However, the speed of recent climate change is very fast. Due to this rapid change, for example cold-blooded animals (a category which includes amphibians, reptiles and all invertebrates) may struggle to find a suitable habitat within 50 km of their current location at the end of this century (for a mid-range scenario of future global warming).

Climate change also increases both the frequency and intensity of extreme weather events, which can directly wipe out regional populations of species. Those species occupying coastal and low-lying island habitats can also become extinct by sea level rise. This has already happened with Bramble Cay melomys in Australia. Finally, climate change has been linked with the increased prevalence and global spread of certain diseases affecting wildlife. This includes Batrachochytrium dendrobatidis, a fungus that is one of the main drivers of the worldwide decline in amphibian populations.

Climate risk is the potential for problems for societies or ecosystems from the impacts of climate change. The assessment of climate risk is based on formal analysis of the consequences, likelihoods and responses to these impacts. Societal constraints can also shape adaptation options. There are different values and preferences around risk, resulting in differences of risk perception.

Common approaches to risk assessment and risk management strategies are based on analysing hazards. This can also be applied to climate risk although there are distinct differences: The climate system is no longer staying within a stationary range of extremes. Hence, climate change impacts are anticipated to increase for the coming decades. There are also substantial differences in regional climate projections. These two aspects make it complicated to understand current and future climate risk around the world. Scientists use various climate change scenarios when they carry out climate risk analysis.

Climate change is already now altering biomes, adversely affecting terrestrial and marine ecosystems. Climate change represents long-term changes in temperature and average weather patterns. This leads to a substantial increase in both the frequency and the intensity of extreme weather events. As a region's climate changes, a change in its flora and fauna follows. For instance, out of 4000 species analyzed by the IPCC Sixth Assessment Report, half were found to have shifted their distribution to higher latitudes or elevations in response to climate change.

Furthermore, climate change may cause ecological disruption among interacting species, via changes in behaviour and phenology, or via climate niche mismatch. For example, climate change can cause species to move in different directions, potentially disrupting their interactions with each other.