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  • 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.

    Rights: The University of Waikato Te Whare Wānanga o Waikato

    The greenhouse effect

    What happens to incoming solar radiation?

    6% is scattered by the atmosphere, 20% is absorbed by the atmosphere and clouds, 20% is reflected by clouds, 49% is absorbed by the Earth's surface and 5% is reflected by the Earth's surface.

    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
    Rights: Dr Katja Riedel

    Ice core showing annual rings

    This is an ice core showing annual rings. The oldest ice ever retrieved was about 950 thousand years old.

    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

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

    Watch Series 1/Episode 2

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

    Greenhouse gases

    Rights: The Royal Society, TVNZ 7 in partnership with the Ministry of Research, Science and Technology

    Greenhouse gases

    This short animated video from TVNZ is a simple explanation of what greenhouse gases are and how they function.

    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
    The ocean, CO₂ and climate change – timeline

    Antarctica tipping points looks at the irreversible changes we could be facing if we fail to keep global warming below 2℃.

    Activity ideas

    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.

    The level 3 Connected article Captured in ice describes how scientists investigate Earth’s climate and supports students to use the science capability ‘Engage with science’.

    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.

    Rights: The University of Waikato Te Whare Wānanga o Waikato

    Ocean acidification

    Our oceans are absorbing about one-third of the carbon dioxide in the atmosphere. As a result, they are becoming more acidic.

    Select here to view point of interest, video transcript and copyright information.

    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
    Tropical Antarctica

    Useful links

    Visit the Climate Change section on the Ministry of Environment website. It includes latest news, reports and explains climate change, its impacts, implications and the New Zealand Government’s overall approach and more.

    A guide to climate change for kids resource from NASA’s Climate Kids web explains climate change science and issues.

    The Ministry of Education's Climate Change Learning Programme, is a level 4 programme focused on climate change that includes specific student activities; the wellbeing guide focuses on student wellbeing and hauora when navigating climate change as an area of learning and action. Many of the suggestions are relevant to other learning levels.

    Scientists continue to research climate change from the unique clues that the Antarctic environment holds. Discover more about Victoria University of Wellington’s Antarctic Research Centre Te Puna Pātiotio’s key research areas and how they approach them. The team won the 2019 Prime Minister’s Science Prize.

    Returning to a green Antarctica is a comic by Simone Giovanardi and Bella Duncan. It explains why Antarctica once looked more like South Island’s West Coast beech forests than the frozen continent we know today.

    Discover lots of great resources on glaciers and climate from the website.

    In 2024 the Journal of the Royal Society of New Zealand released a special issue New Zealand and Antarctica in a changing climate with guest editors James Renwick CRSNZ, Rebecca Priestley CRSNZ, Bruce Glavovic and Darren King.

    Rights: TVNZ, Razor Films, NZ On Air


      Published 24 September 2015 Referencing Hub articles
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