Climate science

IPCC review of farming and forests leaves key questions about effect on climate change "unresolved"

  • 17 Apr 2014, 12:15
  • Robin Webster

The rate at which we're chopping down the world's forests is declining - and in future, crops and newly planted forests could help prevent more climate change, according to the UN.

But uncertainties surrounding how we measure emissions, and what changing temperatures will mean for the world's forests, mean it's hard to be sure this is a good news story.

Emissions from farming, deforestation and other land use are going down, and are expected to continue doing so in the future. By the end of the century, humanity could use the land as a carbon sink, rather than a source of emissions, according to the Panel on Climate Change (IPCC)'s latest  report

It sounds like one piece of good news among  gloomy predictions from the IPCC. But human land use is only one part of a complex picture. 

Climate change could lead to forests  drying out, releasing more carbon dioxide in the atmosphere. And using trees, crops and plants as a source of energy instead of fossil fuels could also lead to more forest destruction.  

Declining emissions

Agriculture, forestry and other land use account for about a quarter (24 per cent) of man-made greenhouse gas emissions. Most of these emissions come from deforestation, changes to the soil and livestock farming.

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Degrees of change: the IPCC’s projections for future temperature rise

  • 15 Apr 2014, 12:00
  • Robin Webster

Many governments are trying to reduce greenhouse gas emissions. But unless policymakers raise their ambition significantly, temperatures are likely to rise beyond safe levels. We examine the pathways that could take us towards a two degrees temperature rise by the end of the century - or considerably higher. 

On Sunday, the Intergovernmental Panel on Climate Change (IPCC) released the last in a series of three reports, which together assess the physical evidence that climate change is happening, the  expected impacts over the course of this century and what would need to happen to curb the rise in greenhouse gases.

Embedded in the reports are the scientists' predictions for how high temperatures are likely to rise this century - and what that's likely to mean for ecosystems and societies around the world. 

Comparing scenarios 

The IPCC bases its projections for future temperature rise on two different techniques. 

First, the IPCC has created its own storylines, or scenarios, describing how high temperatures are likely to rise in the future and what that might mean. The scenarios vary according to different predictions for how societies develop and how much effort we make to reduce greenhouse gas emissions over the course of this century.

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Climate fixes and Plan Bs: The IPCC’s guide to staying below two degrees of global warming

  • 14 Apr 2014, 13:10
  • Roz Pidcock

Cutting emissions, ramping up renewable energy, adapting to a new way of life and sucking carbon dioxide out of the air: recent reports from the Intergovernmental Panel on Climate Change (IPCC) appear to offer a number of ways to limit the scale and seriousness of climate change.

Which are the real climate solutions, and which are pretty risky bets? Here's what the IPCC says about what will and won't work when it comes to fixing the climate.

The two degree target

What we can do to curb the  impacts of climate change is the topic of the  third in a series of recent reports from the IPCC. But when we talk about limiting climate change, what do we really mean?

The idea that we should avoid "dangerous" interference with the climate has been around for a while. But at the UN climate summit in  Cancun in 2010, governments made the goal of keeping warming to no more two degrees Celsius above pre-industrial levels an official target.

The world has already warmed by 0.85 degrees over the industrial period and if emissions stay high, we're on course for more like three to five degrees by 2100, the IPCC  noted in its September report.

In other words, without efforts to reduce warming, we're set to fall a long way short of the target.

RCP2.6-8.0

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