A changing climate

The Earth’s climate is always changing, but the changes are usually very slow – typically taking hundreds to thousands of years. Natural processes such as variations in the Earth’s orbit, solar energy distribution and volcanic eruptions can influence the climate.

Over millions of years, the Earth has alternated between warm and cold periods, but the climate has been fairly stable over the last 10,000 years. This stability has allowed a large variety of different ecosystems (and humans) to establish and flourish.

Human activities in the last century have had an effect on this natural climate balance. Greenhouse gases (carbon dioxide, water vapour, methane and other gases) act like a blanket and cause the Earth to warm. Even small changes in the global average temperature can lead to large shifts in climate and weather.

Antarctica and global climate change

Antarctica is an ideal location to study local-to-global scale climate change. The low diversity of life in the Dry Valleys allows scientists to study it in great detail – including the effects of small climate changes. Scientists think that, once they understand how things work in Antarctica, they can use this knowledge to make predictions about the impacts of climate change elsewhere.

Part of me thinks, ‘Why are we up in the Dry Valleys? If no one ever goes there, why do we need to know anything about them?’ And then you discover that, because it’s such a microbiologically unique environment, it is pretty much the perfect place to look for early indicators of climate change and what the implications of that might be.

Nigel Latta

Antarctica also acts like an archive for ancient history. Small amounts of air get trapped in ice and can reveal climate information from the past. Scientists have charted greenhouse gas levels from as far back as 800,00 years. Ice core data shows that temperatures were warmer when there were more greenhouse gases in the atmosphere and vice versa.

Fossil evidence goes back even further. It shows that, around 45 million years ago, Antarctica resembled a South Island bush ecosystem, with trees, amphibians, insects and fish. Over 10 million years, the climate cooled and the forests were replaced with ice and scrubby grasslands – similar to those found along the central North Island’s Desert Road. Further cooling meant that Antarctica became the ice-covered continent it is today.

Earth’s climate has therefore always changed, but it’s the influence of human impacts that is now causing enormous international concern and activity.

Potential climate change impacts on New Zealand

Climate scientists expect the Earth’s average temperature to increase by between 1°C and 6°C this century. In New Zealand, the Ministry for the Environment predicts the average temperature will rise by about 2°C. While it does not sound like much, warmer temperatures may cause:

  • more frequent extreme weather events such as droughts and floods
  • a need to change land use activities due to changes in rainfall patterns
  • sea level rises and coastal erosion
  • changes to South Island water flows as snowlines and glaciers retreat
  • native ecosystems to be affected by an increase in pest species

On Thin Ice: Nigel Latta in Antarctica

Watch Series 1/Episode 1
www.tvnz.co.nz/ondemand/nigel-latta-in-antarctica/04-03-2015/series-1-episode-1

  • Dry Valleys and climate change monitoring (video timecode 29:14–30:00)

Watch Series 1/Episode 2
www.tvnz.co.nz/ondemand/nigel-latta-in-antarctica/11-03-2015/series-1-episode-2

  • Dry Valleys, weather stations and climate change monitoring (video timecode 24:45–37:20)

Greenhouse gases

Atmospheric greenhouse gases, like carbon dioxide, trap warmth from the Sun and make life possible, but an overabundance of greenhouse gases leads to a rise in global temperatures – known as the greenhouse effect.
Greenhouse effect
Carbon cycle
Timeline – The Ocean in Action

Activity idea

Use these activities to learn more about carbon dioxide and its link to the greenhouse effect.
Greenhouse simulation
Carbon dioxide emissions calculator
Carbon cycle – three-level reading guide

Nature of science

Politics, economics and other social and cultural elements affect the direction of scientific research. It is the role of scientists to provide reliable information regarding climate change. It is up to governments or other decision makers to consider scientific as well as economic and social factors when making policy decisions.

Antarctic research and climate science

Nearly every scientist Nigel visits talks about climate change as a component of their research. The following articles highlight other New Zealand scientists and their involvement with climate change research.

Trapped in ice
Monitoring ozone levels
Ice ages unearthed
Research voyage to Antarctica
Bryozoans and ocean acidification
Argo project
Studying storm surge and coastal hazards
Managing fire risk in the outdoors

Useful links

Visit the Climate Change Information New Zealand website. It briefly explains climate change, its impacts, implications and the New Zealand Government’s overall approach.

NASA’s Climate Kids web resource explains climate change science and issues.

Visit the New Zealand Ministry for the Environment’s School Stuff page for activities including discussion topics, images and interactive, hands-on and field trip ideas.

The Big Chill and the Big Drill, Connected 1 and 2 2008, details how scientists drill cores into the ocean floor to learn about Antarctica’s past and climate change.

 

    Published 24 September 2015