Source: NZ Herald
Climate change is happening, it's almost entirely man's fault
and limiting its impacts may require reducing greenhouse gas
emissions to zero this century, the U.N.'s panel on climate science
The fourth and final volume of the Intergovernmental Panel on
Climate Change's giant climate assessment offered no surprises, nor
was it expected to since it combined the findings of three reports
released in the past 13 months.
But it underlined the scope of the climate challenge in stark
terms. Emissions, mainly from the burning of fossil fuels, may need
to drop to zero by the end of this century for the world to have a
decent chance of keeping the temperature rise below a level that
many consider dangerous.
The IPCC did not say exactly what such a world would look like
but it would likely require a massive shift to renewable sources to
power homes, cars and industries combined with new technologies to
suck greenhouse gases from the atmosphere.
The report warned that failure to reduce emissions could lock
the world on a trajectory with "irreversible" impacts on people and
the environment. Some impacts already being observed included
rising sea levels, a warmer and more acidic ocean, melting glaciers
and Arctic sea ice and more frequent and intense heat waves.
"Science has spoken. There is no ambiguity in their message.
Leaders must act. Time is not on our side," U.N. Secretary-General
Ban Ki-moon said at the report's launch in Copenhagen.
Amid its grim projections, the report said the tools are there
to set the world on a low-emissions path and break the addiction to
burning oil, coal and gas which pollute the atmosphere with
heat-trapping CO2, the chief greenhouse gas.
"All we need is the will to change, which we trust will be
motivated by knowledge and an understanding of the science of
climate change," IPCC chairman Rajendra Pachauri said.
The IPCC was set up in 1988 to assess global warming and its
impacts. The report released Sunday caps its latest assessment, a
mega-review of 30,000 climate change studies that establishes with
95-percent certainty that most of the warming seen since the 1950s
is man-made. The IPCC's best estimate is that just about all of it
is man-made, but it can't say that with the same degree of
Today only a small minority of scientists challenge the
mainstream conclusion that climate change is linked to human
Global Climate Change, a NASA website, says 97 percent of
climate scientists agree that warming trends over the past century
are very likely due to human activities.
The American public isn't as convinced. A year-old survey by Pew
Research showed 67 percent of Americans believed global warming is
occurring and 44 percent said the earth is warming mostly because
of human activity. More recently, a New York Times poll said 42
percent of Republicans say global warming won't have a serious
impact, a view held by 12 percent of Democrats and 22 percent of
Sleep-deprived delegates approved the final documents Saturday
after a weeklong line-by-line review that underscored that the IPCC
process is not just about science. The reports must be approved
both by scientists and governments, which means political issues
from U.N. climate negotiations, which are nearing a 2015 deadline
for a global agreement, inevitably affect the outcome.
The rift between developed and developing countries in the U.N.
talks opened up in Copenhagen over a passage on what levels of
warming could be considered dangerous. After a protracted battle,
the text was dropped from a key summary for policy-makers to the
disappointment of some scientists.
"If the governments are going to expect the IPCC to do their
job," said Princeton professor Michael Oppenheimer, a lead author
of the IPCC's second report, they shouldn't "get caught up in
fights that have nothing to do with the IPCC."
The omission meant the word "dangerous" disappeared from the
summary altogether. It appeared only twice in a longer underlying
report compared to seven times in a draft produced before the
Copenhagen session. The less loaded word "risk" was mentioned 65
times in the final 40-page summary.
"Rising rates and magnitudes of warming and other changes in the
climate system, accompanied by ocean acidification, increase the
risk of severe, pervasive, and in some cases irreversible
detrimental impacts," the report said.
World governments in 2009 set a goal of keeping the temperature
rise below 2 degrees C (3.6 F) compared to before the industrial
revolution. Temperatures have gone up about 0.8 C (1.4 F) since the
Emissions have risen so fast in recent years that the world has
used up two-thirds of its carbon budget, the maximum amount of CO2
that can be emitted to have a likely chance of avoiding 2 degrees
of warming, the IPCC report said.
"This report makes it clear that if you are serious about the
2-degree goal ... there is nowhere to hide," said Alden Meyer of
the Union of Concerned Scientists, an advocacy group. "You can't
wait several decades to address this issue."
U.S. Secretary of State John Kerry said the report demands
"ambitious, decisive and immediate action."
"Those who choose to ignore or dispute the science so clearly
laid out in this report do so at great risk for all of us and for
our kids and grandkids," Kerry said in a statement.
The IPCC said the cost of actions such as shifting to solar and
wind power and other renewable sources and improving energy
efficiency would reduce economic growth only by 0.06 percent
Pachauri said that should be measured against the implications
of doing nothing, putting "all species that live on this planet" at
The report is meant as a scientific roadmap for the U.N. climate
negotiations, which continue next month in Lima, Peru. That's the
last major conference before a summit in Paris next year, where a
global agreement on climate action is supposed to be adopted.
The biggest hurdle is deciding who should do what. Rich
countries are calling on China and other major developing countries
to set ambitious targets; developing countries saying the rich have
a historical responsibility to lead the fight against warming and
to help poorer nations cope with its impacts. The IPCC avoided
taking sides, saying the risks of climate change "are generally
greater for disadvantaged people and communities in countries at
all levels of development."