NOTE: This glossary defines the key terms used on this website when discussing the GHG crisis ("climate change").  A glossary is necessary because the terms used to address this crisis have been flagrantly distorted.  Where the IPCC definition is used, this is noted.  My own terms, which were coined to fill certain gaps, are identified with "(FR)".  My comments are highlighted in grey.

Assessment reports:

The set of reports delivered by the IPCC on a roughly six-year cycle.  The first (AR1) appeared in 1990.  This was followed by AR2 in 1995, AR3 in 2001, AR4 in 2007, and AR5 in 2014.  Most of AR6 is scheduled for 2021.  The report's format has changed since AR1, but the core now comprises three volumes: The Physical Science Basis; Impacts, Adaptation, and Vulnerability; and Mitigation of Climate Change.

The AR5 volumes collectively contain over 5,000 pages. Having perused them all, my impression is that they are data dumps, intended to overwhelm rather than provide practical guidance. The most egregious volume is Mitigation of Climate Change, which should fulfill the IPCC's original mandate to provide "realistic response strategies" (see "IPCC" below). First, "mitigation" by definition excludes SRM, so the response strategies omit this critical measure. Second, in AR5 this volume failed to offer any response to the Arctic emergency.

Carbon budget:

The GHG quantities that can purportedly be emitted while remaining below a "safe" temperature threshold such as 1.5°C or 2°C.

Because the rational GHG aim is safe concentrations, which were exceeded around 1970, humankind's carbon budget has been negative for about fifty years.

Climate change:

A prolonged change in the mean and variability of key weather components. (IPCC: AR5 glossary).  As indicated by this diagram, climate change is one of several effects of global warming.

This term is frequently used to refer to the full range of harmful GHG effects, which is logically and scientifically untenable.  I therefore use "GHG crisis" for this purpose.

Ecological crisis:

The GHG crisis and the various non-GHG impacts (habitat destruction, over-exploitation, pollution, wastes, etc.) that have resulted from ecological overshoot.

Ecological overshoot:

The violation of multiple significant environmental limits, starting around 1950, due to the over-expansion of the global capitalist economy.

Ecological damage function:

The relationship between elevated global temperatures and ecological damage.  (FR)

My claim, which was confirmed by the IPCC in its 1.5°C report (SPM, p. 5), is that this damage is a function of the speed, magnitude, and duration of elevated temperatures.  Although duration is mentioned in the report's SPM (Summary for Policymakers), it is completely ignored in the full report.  Why?  Because it would expose the fact that stabilizing the global temperature at 1.5°C or 2°C fails to solve the problem: an unsafe temperature would continue to damage the environment into the indefinite future.  The only rational solution is a safe global temperature through safe concentrations.

Emission scenarios:

The various emission trajectories offered by the IPCC to policymakers for their implementation.  Compare: "safe concentration scenarios".

All these scenarios lead to higher and thus increasingly unsafe GHG concentrations.  Also, because emission scenarios are the main analytical tool in the IPCC's assessment reports, they divert attention away from the actual problem of unsafe GHG concentrations.

Emissions fallacy:

The irrational focus on reduced emissions when the GHG problem is unsafe concentrations.

Emissions are increments to concentrations, so reducing them can only slow or halt their increase.  This fallacy is at the core of the IPCC's ecocidal strategy: to bend the net-emissions curve to zero rather than the concentrations curve to its safe level.  See this post.

Energy balance:

The quantitative relationship between the energy flowing from the Sun to the Earth and from the Earth into space.  The Earth is in energy balance when these flows are equal.  Unsafe GHG concentrations have caused a serious energy imbalance, which manifests itself as global warming.


The use of various methods to reduce the Earth's energy imbalance and thus global warming.  There are two categories: solar radiation management (SRM), which decreases the inflow of solar energy, and GHG removal, which increases the outflow of terrestrial energy.

GHG crisis:

The full set of harmful effects from unsafe GHG concentrations. (FR)  These effects are global warming and its various effects, plus ocean acidification.

A term such as this is desperately needed because the commonly-used "climate change" (or "climate crisis", etc.) is patently incorrect for this purpose.  A changing climate is only one of several effects of global warming, and it excludes ocean acidification.

GHG removal (GGR):

The removal of GHGs from the environment by natural or technical means.  This is one of the two categories of geoengineering, the other being SRM.

Although the fact is frequently ignored, GHG removal is also the sink-enhancement component of mitigation - see the definition below.  The glossary for the 1.5°C report nevertheless states that the removal of CO2 (CDR), "... is classified as a special type of mitigation." It fails to explain why one half of the official, longstanding definition of "mitigation" is in any way special.

Global warming:

The gradual increase in global surface temperature as one of the consequences of radiative forcing caused by anthropogenic emissions.  (IPCC: AR5 glossary).  In simpler language this refers to the warming of the Earth's surface by the rise in GHG concentrations since the Industrial Revolution.  Global warming is the main component of the GHG crisis.  It is related to but conceptually distinct from climate change.

Impact reduction:

The reduction of GHG or non-GHG impacts through the three IPAT factors: lower consumption, lower population, and higher efficiencies. (FR)

Intergovernmental Panel on Climate Change (IPCC):

The organization established in 1988 by two United Nations agencies - UNEP (UN Environment Programme) and the WMO (World Meteorological Association) - in response to the GHG crisis.  Its mandate was to assess the scientific information relating to the crisis and to formulate, "... realistic response strategies for the management of the climate change issue."  As discussed in Ecological Survival and Revolutionary Change  (section A3), the IPCC's actual purpose was likely to sideline the deeply concerned scientists who were independently raising the alarm about global warming at this time.

Linear fallacy:

The assumption that any impact reduction will result in a proportional harm reduction, thereby ignoring the existence of tipping points and points of no return.  (FR)

The IPCC mentions non-linear "surprises" when discussing GHG problems, but ignores them when discussing solutions.  The organization never mentions points of no return.


A human intervention to address the GHG crisis by reducing the sources or enhancing the sinks of GHGs.  (IPCC: AR5 glossary)

Note that the term includes BOTH emissions reductions (sources) and GGR (sinks).  Despite this, the sink side is frequently ignored and "mitigation" is taken to mean emissions reductions alone.  Also note that the term relates to the GHG crisis, not to emissions.  Despite common usage, emissions should be reduced, lowered, or minimized, but not mitigated.  The IPCC glossary makes this explicit by listing the term as "Mitigation (of climate change)".

Negative emissions:

The removal of GHGs from the atmosphere by deliberate human activities.  (IPCC: 1.5°C glossary).

This term is superfluous because its meaning is already covered by GGR.  It is also potentially deceptive because it can be used to falsely imply that emissions must be reduced to zero before removals can begin.

Net-zero emissions:

The stabilization of GHG concentrations when removals are equal to emissions.

As a response strategy for the GHG crisis this is ecocidal because unsafe concentrations will continue to increase until net-zero emissions are achieved, and ecological damage will continue to escalate until safe concentrations are reached.  A critical point is that reaching net-zero emissions is logically equivalent to reaching peak concentrations.

Point of no return:

The point in an ecosystem's degradation where damage is so great that human agency no longer suffices to prevent ecosystem collapse.  Compare with "tipping point", where human agency still exists.

Problem denialism:

Refusal to accept that the GHG crisis is real or serious.  (FR)  Compare: solutions denialism.

This is my term for the "denialism" that is correctly opposed by the IPCC and environmentally concerned, but which ignores the fact that there are two types of denialism: problem and solutions.

Safe concentration scenarios:

Possible GHG concentration trajectories that lead to safe concentration levels.  Compare: "emission scenarios".

These are the scenarios that an honest organization would be proposing to policymakers for their implementation.  For further discussion, see this post.

Safe concentrations:

GHG concentrations that do not cause environmental harms.  This is both the rational goal for the GHG crisis and the key objective in the 1992 UNFCCC agreement (see "UNFCCC" below).

Solar Radiation Management (SRM):

The various methods used to block a fraction of the Sun's radiation in order to restore the Earth's energy balance.  This is one of the two categories of geoengineering, the other being GGR.  Unlike GGR, SRM is unrelated to GHG sources or sinks, and therefore is not part of mitigation.

Solutions denialism:

Refusal to fully accept the rational response to the ecological crisis. (FR)  This response includes SRM, GGR, impact reduction, and ecological restoration. Compare: "problem denialism".


A term that is frequently used by SRM opponents to disparage this critical measure.  It paints SRM as a reckless, "mad scientist" substitute for emissions reductions.  For a good example see The Madhouse Effect by climate scientist Michael Mann.  Here he refers to, "... the technofix schemes proposed as purported solutions to the problem of human-caused climate change." (p. 118)  This is clearly a straw-man argument because it ignores SRM's rational application - see "Techno-shield" below.


The rational use of SRM as a temporary, stopgap measure to arrest the Earth's growing energy imbalance while emissions are sharply reduced and unsafe GHG concentrations are removed from the atmosphere. (FR)

Temperature threshold:

The use of a temperature limit such as 1.5°C or 2°C as the goal for the GHG crisis.

Such a goal is disastrous for two reasons.  First, ecological damage is caused not just by the magnitude of an elevated temperature, but also by the speed of its rise and its duration.  Second, relating emission scenarios to their resulting temperature increases is fraught with uncertainties.  The IPCC's temperature-based 1.5°C report, for example, employs the word "uncertainty" and its variants more than 300 times.

Tipping point:

The point in an ecosystem's degradation where damage increases sharply due to positive feedbacks, cascading harms, or other factors.  At this point human agency still exists and ecosystem collapse can be prevented with an adequate response.  Compare with "point of no return", where human agency no longer exists.

United Nations Framework Convention on Climate Change (UNCFCCC):

An international agreement adopted in 1992 and ratified in 1994. The agreement's core statement is that participating nations are, "Determined to protect the climate system for present and future generations ..." through the "... stabilization of greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system."

This critical agreement, which offers a rational approach to the GHG crisis, has been effectively repudiated.