Human influence on climate change is ‘clear’, claims IPCC, as NASA reacts with future forecast

27 Sep 2013

The Intergovernmental Panel on Climate Change (IPCC) has today released the findings of its latest, and fifth, assessment on climate change and its causes. It is claiming it’s “extremely likely” that the action of human beings has been the dominant cause of the observed warming since the mid-20th century. NASA, meanwhile, has reacted to the news and has compiled visual data on what the future climate might look like.

Today’s assessment from the IPCC has scientists reacting in various ways to its latest discoveries about climate change.

Climate modelling

The IPCC has compiled its latest data on the climate system based on direct measurements and remote sensing from satellites and other platforms.

“Human influence on the climate system is clear. This is evident in most regions of the globe,” the IPCC confirmed today in a statement, following a plenary session that took place in Stockholm, Sweden, this week. This plenary wrapped up yesterday.

The latest IPPCC assessment, the final report of which will be published on Monday, will aim to provide a clear view of the current state of scientific knowledge relevant to climate change.

Each of the past three decades – progressively warmer

Among the findings the IPCC has revealed today is that it is “extremely likely” that human influence has been the “dominant” cause of the observed warming since the mid-20th century.

The IPCC said the evidence for this has morphed, thanks to more and better observations, an improved understanding of the climate system response, and improved climate models.

“Warming in the climate system is unequivocal and since 1950 many changes have been observed throughout the climate system that are unprecedented over decades to millennia.

“Each of the last three decades has been successively warmer at the Earth’s surface than any preceding decade since 1850,” the IPCC reported.

“Our assessment of the science finds that the atmosphere and ocean have warmed, the amount of snow and ice has diminished, the global mean sea level has risen and the concentrations of greenhouse gases have increased,” said Qin Dahe, co-chair of IPCC Working Group I.

In addition, Thomas Stocker, the other co-chair of this Working Group, said that continued emissions of greenhouse gases will cause further warming and changes in all components of the climate system.

“Limiting climate change will require substantial and sustained reductions of greenhouse gas emissions,” he said.

The IPCC predicts that global surface temperature change for the end of the 21st century could be likely to exceed 1.5°C relative to 1850 to 1900, in all but the lowest scenario considered, and likely to exceed 2°C for the two high scenarios.

And it seems that the planet is also going to be hit with more heatwaves. Such heatwaves are also likely to last longer, according to the IPCC.

“As the Earth warms, we expect to see currently wet regions receiving more rainfall, and dry regions receiving less, although there will be exceptions,” explained Stocker.

Global-scale observations from the instrumental era began in the mid-19th century for temperature and other variables, with more comprehensive and diverse sets of observations available for the period 1950 onwards, the IPCC said.

“As a result of our past, present and expected future emissions of CO2, we are committed to climate change, and effects will persist for many centuries even if emissions of CO2 stop,” said Stocker.

Qin Dahe, co-chair of the IPCC report, said that as the ocean warms, and glaciers and ice sheets reduce, global mean sea level will continue to rise.

This rise in sea levels will happen at a “faster rate than we have experienced over the past 40 years”, added Dahe.

The summary for policymakers of the Working Group I contribution to the IPCC Fifth Assessment Report is available online.

US space agency NASA has reacted to the IPCC findings by releasing new data visualisations from the NASA Center for Climate Simulation and NASA’s Scientific Visualization Studio.

The following video from NASA will aim to depict how the climate models used in the new report from the IPCC estimate how temperature and precipitation patterns could change throughout the 21st century.

View of Planet Earth with some clouds via Shutterstock

Carmel Doyle was a long-time reporter with Silicon Republic