atmosphere. Forests and other vegetation are considered sinks because they remove CO2 through photosynthesis. Source: Any process, activity or mechanism that releases a GHG, an aerosol or a precursor of a GHG or aerosol into the atmosphere. Sustainable development: Development that meets the needs of the present without compromising the ability of future generations to meet their own needs. Technology transfer: A broad set of processes covering the flows of know-how, experience and equipment for mitigating and adapting to climate change among different stakeholders. Temperature overshoot: An emission pathway that temporarily exceeds target temperature limits (2°C or 1.5°C) before falling below the limits again by 2100 with a given percentage chance. Tipping point: A level of change in system properties beyond which a system reorganizes, often abruptly, and does not return to the initial state even if the drivers of the change are abated. For the climate system, it refers to a critical threshold when global or regional climate changes from one stable state to another stable state. The tipping point event may be irreversible. Top-down model: A model that applies macroeconomic theory, econometric and/or optimization techniques to aggregate economic variables. Using historical data on consumption, prices, incomes, and factor costs, topdown models assess demand and emissions for goods and services from main sectors, such as energy conversion, transportation, buildings, agriculture and industry.
Transient climate response: Measure of the temperature rise that occurs at the time of a doubling of carbon dioxide concentration in the atmosphere. Transient climate response to cumulative carbon emissions: Measure of temperature rise per unit of cumulative carbon emissions. Uncertainty: A cognitive state of incomplete knowledge that can result from a lack of information or from disagreement about what is known or even knowable. It may have many types of sources, from imprecision in the data to ambiguously defined concepts or terminology, or uncertain projections of human behaviour. Uncertainty can therefore be represented by quantitative measures (for example a probability density function) or by qualitative statements (for example reflecting the judgement of a team of experts). Unconditional INDCs: INDCs proposed by countries without conditions attached. Wide-scale restoration: Aims to restore closed forests to the landscape. This type of restoration is more likely in deforested or degraded landscapes with low population density (<10 people/km2) that are also areas where closed forests formerly dominated the landscape. 2020 pledge: See Cancun pledge. 20th–80th percentile range: Results that fall within the 20–80 per cent range of the frequency distribution of results in this assessment.
The Emissions Gap Report 2015 – Glossary
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