Skip to content

Evidence & Impacts: IPCC

Image: IPCC

Home > Climate wiki > Evidence > IPCC Intergovernmental Panel on Climate Change

IPCC: Intergovernmental Panel Climate Change

Summary

Current reports

“Climate change is widespread, rapid, and intensifying… Many of the changes observed in the climate are unprecedented in thousands, if not hundreds of thousands of years, and some of the changes already set in motion—such as continued sea level rise—are irreversible over hundreds to thousands of years.” – IPCC August 2021

Video 1: IPCC 6th Assessment Report: Impacts, Adaptation and Vulnerability

Home > Climate wiki > Evidence > IPCC Intergovernmental Panel on Climate Change

Summary

Current reports

“Climate change is widespread, rapid, and intensifying… Many of the changes observed in the climate are unprecedented in thousands, if not hundreds of thousands of years, and some of the changes already set in motion—such as continued sea level rise—are irreversible over hundreds to thousands of years.” – IPCC August 2021

Video 1: IPCC 6th Assessment Report: Impacts, Adaptation and Vulnerability

Sixth Assessment Report 2021-22

“I’ve seen many scientific reports in my time but nothing like this. Today’s IPCC report is an atlas of human suffering and the damning indictment of failed climate leadership. This report reveals that all people on the planet are getting clobbered by climate change. Nearly half of humanity is living in the danger zone. Now. Many ecosystems are at the point of no return. Now. And unchecked carbon pollution is forcing the globe’s most vulnerable on a frog march to destruction. Now. The facts are undeniable. This abdication of leadership is criminal.” – António Guterres, Secretary-General of the United Nations introduction to the IPCC Sixth Assessment Report II: Impacts, Adaptation and Vulnerability

Video 2: IPCC 6th Assessment Report III: Mitigation (press conference)
Fig. 1: To see an interactive map, click on the image. This will take you to the IPCC website. This screengrab is an example of how you can enter specific information for regions (in this example, New Zealand/ land only) and check the projected temperature changes over time, based on different models and pathways (i.e. if and by how much we reduced emissions).

Background

Back in 1988 when it was clear that the world’s climate was changing, it was also evident that every aspect of life on Earth would be affected. The IPCC was formed to gather research from around the world, evaluate it, and use it to make predications about the impacts, with the objective of ‘stablising greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic (human-induced) interference with the climate system‘. By gathering research from across all sectors, the IPCC is also able to see where there are gaps in knowledge, which in turn helped direct research.

Each of the six Assessment Reports published since 1988 runs into several million words, are in several parts, and collated over four to five years by scientists and researchers nominated by their respective governments (Fig. 2). This process ensures that:

  1. All member nations are represented
  2. There is time to include all relevant material
  3. A consensus is reached by all nations prior to each Assessment Report being released

Thousands of scientists and other experts around the world volunteer their time to write and review the draft reports. As these are long and technical to ensure the research is robust and comprehensive, there is also a summary report for policymakers. Delegates from all participating governmentsaround 120 including New Zealandcheck the summary report line-by-line, and all countries have to agree on the wording before the final report is published.

The Sixth Assessment Report is now underway. The first report in this cycle, the Physical Science, and the second report, Impacts, Adaptation and Vulnerability have now been published.

Fig. 2: The process or ‘cycle’ of each of the reports. The cycle of the sixth report is now underway and due to be completed in 2022. The first report in the sixth cycle, published August 2021, includes peer-reviewed science published prior to January 31, 2021. Research published after that date is not included due to the time it takes to collate and review material (Image: IPCC).

Criticisms of reports being too conservative

Some assumptions in the first five assessment cycles (AR1-5) have not come to pass. These assumptions were primarily that:

Some nations still reject aspects of the science and implications of climate change, insisting on language in the summary reports downplay the scale and urgency of the problems. As few read more than the summary reports, the nuances are often lost or overlooked by policy makers.

Supporting evidence: It takes time, sometimes years to gather robust data, write research papers and have that research published. Consequently, some research in IPCC reports is more than a decade old. In research fields such as the process that lead to ice-caps melting, it was (and still is) an evolving field of science, and so summary reports did not include the potential of this to lead to rapid sea level rise, because it was an unknown. Hence, by the time IPCC reports are released, real-world events and discoveries have already taken place. For example, IPCC predictions about sea level rise and temperatures regarded the ‘worst case scenario’ to be the ‘least likely’. On the eve of the Fourth Assessment Report a study was published showing that temperatures were at the top end of the worst predictions (blue-dotted line), and sea levels were rising much faster that the ‘worst case’ scenario (grey shaded area) (Fig. 3).

This problem of a lack of data and out-dated research is crucial, given that data in the 2013 Fifth Assessment Report used as the basis of the 2015 Paris Agreement to keep global temperatures under 1.5°C was itself based on research as much as 10 year old. Interim reports have focused on specific issues that take into account more recent observations and research:

Fig. 3: Changes in key global climate parameters since 1973. Top: Monthly carbon dioxide concentrations; different colours are from different measuring stations. Middle: annual global-mean surface temperature; the grey area are IPCC projections). Bottom: sea-level data based on tide gauges and satellite altimeter; the grey area are IPCC projections, the top line shows what was actually observed.
Video 2: IPCC State of the Oceans and Crysophere (7 minutes)
Video 3: IPCC State of the Oceans and Crysophere (56 minutes)

More information