The Heat is On – Time to Act on Climate Change

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A new assessment by the Intergovernmental Panel on Climate Change (IPCC) claims that the warming of the climate system is unequivocal, and its effects are now evident in most regions of the world.

Since the 1950s, many of the observed changes are unprecedented over decades to millennia. The atmosphere and ocean have warmed, the amounts of snow and ice have diminished, sea level has risen, and the concentrations of greenhouse gases have increased. Each of the last three decades has been successively warmer at the Earth’s surface than any preceding decade since 1850. In the Northern Hemisphere, 1983–2012 was likely the warmest 30-year period of the last 1400 years. Breaking more temperature records than in any other decade.

The authors of the new report on the physical evidence for climate change state that continued emissions of greenhouse gases will cause further warming and changes in all components of the climate system.

The Global surface temperature change for the end of the 21st century is projected to 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. Heat waves are very likely to occur more frequently and last longer.

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

It is the poorest regions of the world and the most vulnerable individuals such as the young and elderly who will be most affected.

Limiting climate change will require substantial and sustained reductions of greenhouse gas emissions. This will require international action to adopt ambitious legal agreement on climate change in 2015. We will only know over the next year or whether the new evidence will have any impact on national governments who are preoccupied with stimulating growth, reducing debt and increasing employment.

The  assessment draws on millions of observations and over 2 million gigabytes of numerical data from climate model simulations. Over 9,200 scientific publications are cited, more than three quarters of which have been published since the last IPCC assessment in 2007.

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Key evidence highlighted in the report is given below with levels of confidence:

  • Ocean warming dominates the increase in energy stored in the climate system, accounting for more than 90% of the energy accumulated between 1971 and 2010 (high confidence). It is virtually certain that the upper ocean (0−700 m) warmed from 1971 to 2010, and it likely warmed between the 1870s and 1971.
  • Over the last two decades, the Greenland and Antarctic ice sheets have been losing mass, glaciers have continued to shrink almost worldwide, and Arctic sea ice and Northern Hemisphere spring snow cover have continued to decrease in extent (high confidence).
  • The rate of sea level rise since the mid-19th century has been larger than the mean rate during the previous two millennia (high confidence). Over the period 1901–2010, global mean sea level rose by 0.19 [0.17 to 0.21] m.
  • The atmospheric concentrations of carbon dioxide (CO2), methane, and nitrous oxide have increased to levels unprecedented in at least the last 800,000 years.
  • CO2 concentrations have increased by 40% since pre-industrial times, primarily from fossil fuel emissions and secondarily from net land use change emissions. The ocean has absorbed about 30% of the emitted anthropogenic carbon dioxide, causing ocean acidification.
  • Total radiative forcing is positive, and has led to an uptake of energy by the climate system. The largest contribution to total radiative forcing is caused by the increase in the atmospheric concentration of CO2 since 1750.
  • Human influence on the climate system is clear. This is evident from the increasing greenhouse gas concentrations in the atmosphere, positive radiative forcing, observed warming, and understanding of the climate system.
  • Climate models have improved since the last 2007 of assessment of the physical evidence on cliamte change. Models reproduce observed continental-scale surface temperature patterns and trends over many decades, including the more rapid warming since the mid-20th century and the cooling immediately following large volcanic eruptions (very high confidence).
  • Observational and model studies of temperature change, climate feedbacks and changes in the Earth’s energy budget together provide confidence in the magnitude of global warming in response to past and future forcing.cc
  • Human influence has been detected in warming of the atmosphere and the ocean, in changes in the global water cycle, in reductions in snow and ice, in global mean sea level rise, and in changes in some climate extremes. This evidence for human influence has grown since the last assessment. It is extremely likely that human influence has been the dominant cause of the observed warming since the mid-20th century.
  • 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.
  • Global surface temperature change for the end of the 21st century is likely to exceed 1.5°C relative to 1850 to 1900 for all  scenarios except RCP2.6. It is likely to exceed 2°C for RCP6.0 and RCP8.5, and more likely than not to exceed 2°C for RCP4.5.
  • Warming will continue beyond 2100 under all RCP scenarios except RCP2.6. Warming will continue to exhibit interannual-to decadal variability and will not be regionally uniform.
  • Changes in the global water cycle in response to the warming over the 21st century will not be uniform. The contrast in precipitation between wet and dry regions and between wet and dry seasons will increase, although there may be regional exceptions.t767375a
  • The global ocean will continue to warm during the 21st century. Heat will penetrate from the surface to the deep ocean and affect ocean circulation.
  • It is very likely that the Arctic sea ice cover will continue to shrink and thin and that Northern Hemisphere spring snow cover will decrease during the 21st century as global mean surface temperature rises. Global glacier volume will further decrease.
  • Global mean sea level will continue to rise during the 21st century. Under all RCP scenarios the rate of sea level rise will very likely exceed that observed during 1971–2010 due to increased ocean warming and increased loss of mass from glaciers and ice sheets.
  • Climate change will affect carbon cycle processes in a way that will exacerbate the increase of CO2 in the atmosphere (high confidence). Further uptake of carbon by the ocean will increase ocean acidification.
  • Cumulative emissions of CO2 largely determine global mean surface warming by the late 21st century and beyond. Most aspects of climate change will persist for many centuries even if emissions of CO2 are stopped. This represents a substantial multi-century climate change commitment created by past, present and future emissions of CO2.

The  report increases in the confidence associated with climate observations but whichever facts may be discussed, debated or distorted, we cannot ignore the reality that we must act or face frightening new impacts.

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Meltdown of Public Opinon on Climate Change

RECENT events are now resulting in more people questioning the validity of the science behind climate change. Could this be the beginning of a meltdown in public opinion on global warming?

RECENT events are now resulting in more people questioning the validity of the science behind climate change. Could this be the beginning of a meltdown in public opinion on global warming?

The recent period of freezing temperatures and the failure of the Copenhagen climate summit to agree legally binding greenhouse gas targets provided the backdrop for two events that have threatened the creditability of climate change science.

The “Climategate” fiasco saw the contents of emails stolen from the University of East Anglia’s Climatic Research Unit leading to accusations that a number of researchers had manipulated data.

Meanwhile, the Intergovernmental Panel on Climate Change (IPCC), the leading body for the assessment of the scientific evidence of climate change, admitted it had got it wrong on predicting Himalayan glaciers could disappear by 2035.

Taken all together, it is not surprising that the general public is beginning to question whether climate change is really happening. A recent BBC Poll suggests that scepticism about climate change is on the rise. Of the 1,001 adults polled, 25 per cent did not think global warming was happening.

This is a 10 per cent increase on a similar poll that was conducted last year. Those who said climate change was real had fallen from 83 to 75 per cent. Only 26 per cent believed that climate change was happening and was largely the result of human activities.

Climate change is unlike any other environmental issue. For some, it is seen as a new religion with those sceptical of the evidence labelled “deniers” as if they were questioning the existence of a divine being. Unless you live on a small island state such as Tuvalu, near Fiji, which is slowly sinking due to the rising sea level, it is easy to think climate change is a myth.

There is also public confusion over the difference between weather – atmospheric conditions over hours or days – and climate – changes in the atmosphere over years. This has led some people to think that the recent heavy snowfall and sub-zero temperatures are sufficient evidence that global warming is not real.

How climate change is communicated plays a powerful role in influencing public attitudes and determining whether people are willing to reduce their carbon footprint. The alarmist language used by the media to describe the potential impact of climate change has been referred to as “climate porn” – offering a thrilling spectacle but ultimately distancing the public from the problem. The use of apocalyptic media images of receding glaciers, scorched land, flooded metropolises and polar bears grappling for survival all foster public apathy.

It is no wonder the public feels disempowered. The issue is portrayed as being so big and multifaceted that it seems unreal and more like science fiction rather than science fact.

Climate sceptics are quick to claim that Climategate and the “Glaciergate” are evidence of “dodgy” climate science. While a few points in the IPCC report may be incorrect, this does not invalidate the last four assessments of the basic science of climate change. There is overwhelming evidence to suggest that global warming is due to human activity.

The reality is that climate science is still developing as new evidence comes to light. We are still trying to understand the complexity of the global climate system and the effect and speed of different feedback mechanisms.

For example, a scientific survey of Siberian tundra coastlines has reported methane levels are roughly 100 times above normal. Methane is a greenhouse gas 20 times more powerful than carbon dioxide.

More than 10 times the annual global greenhouse emissions are thought to be trapped in tundra across the world. As the tundra thaws will it become a “Methane Bomb”?

Health damaging particles in polluting gases emitted by industry, traffic and domestic heating have a “cooling” effect on the climate. In reducing local air pollution are we lowering this cooling effect and inadvertently accelerating global warming?

Many questions such as these require further scientific investigation.

It is too easy to dismiss the whole climate change issue as mass hysteria. Prevention is always much better than cure. It is right that we take action now to reduce greenhouse gas emissions, adapt to predicted climate change and move to a low carbon economy.

We need to become more efficient in our energy use and develop renewable energy sources. After all, whether climate change happens or not, we still have to face up to the fact of dwindling oil reserves and our over-consumption of natural resources.

Whatever doubt we may have about climate science, or whether climate change is really happening, a fundamental question remains – are we willing to gamble with our children’s future on this planet?

© Gary Haq 2010
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