In late July this year, Dr James Renwick, head of Victoria University School of Geography, Environment and Earth Sciences, shared his knowledge about climate change with an audience which packed-out the Davis Theatre at Whanganui Regional Museum.

Professor Renwick has nearly 40 years of experience in weather and climate research, specialising in large-scale climate variability and change, including climate impacts on New Zealand and Antarctica.

He has a special interest in Antarctic climate, especially the growth and decay of Antarctic sea ice.

He is also interested in how atmospheric circulation affects the extent of sea ice.

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A lead author for the last two Assessment Reports of the Intergovernmental Panel on Climate Change (IPCC), he will also be a Convening Lead Author for the sixth IPCC Assessment.

Professor Renwick described where climate change is at right now, how much sea level rise we should expect and plan for and whether it is possible to stop global warming at 1.5°C.

He outlined how the earth's temperature is governed by two key inputs: solar radiation and the thickness of the earth's atmosphere.

This acts like an insulating blanket around the planet that deflects and radiates heat back into space and traps warmth on the earth's surface, 93 per cent of which is stored in the oceans.

Although carbon dioxide (CO2) is only a very small fraction of the atmosphere, it has a large effect on the earth's temperature.

Professor Renwick presented a graph tracking atmospheric CO2 over the last 200 years, based on data collection from a variety of sources, including dissolved air in ice-core samples and weather stations around the globe.

The increase in CO2 is measurable and irrefutable.

The warming effect of this atmospheric blanket is measurable and irrefutable.

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The increase of sea level as the warmed ocean expands is measurable and irrefutable.

In the Museum, I recently found an article titled Earth Warming, published on 15 April 1957 and reprinted in Good Morning New Zealand - News Stories of the Day from the 1950s.

Margie Beautrais.
Margie Beautrais.

The article quotes Dr Joseph Kaplan, a University of California professor and head of the International Geophysical Year (a multi-nation scientific study of the earth).

"We are changing Earth's atmosphere. The burning of fuels is of such great magnitude that the discharged gases are creating a greenhouse effect over the planet".

Dr Kaplan predicted this would have a great effect on the Arctic and Antarctic ice masses.

Joseph Kaplan, like James Renwick, was part of a collaboration of scientists across the globe, studying the earth, recording all kinds of measurements and reporting on their findings.

In 1957-1958, nearly 80,000 scientists and volunteers from 67 countries gathered data at 8000 stations from pole to pole.

The report included a comment that the study "gave proof that however many and serious the political problems that trouble the human race, it is possible for nations to work together in a great enterprise planned for the common good."

That was 62 years ago.

Multitudinous scientific studies later, data about the earth, the poles, the atmosphere and our effect on all of these are still being gathered and measured at hundreds of sites.

Scientists everywhere continue to report on the data and make predictions about what will happen next.

Since the 1950s, the increase in atmospheric carbon has been exponential. The consensus of climate scientists about anthropogenic climate change is now greater than 99 per cent.

I hope that what will happen next is that we do "work together in a great enterprise planned for the common good".

It is possible for all of us to help cut New Zealand's carbon emissions.

We can reduce our own use of fossil fuels. We can buy more locally produced food or grow some of our own.

We can help with the nationwide plan to plant a billion trees by adding a few to our own garden, school or neighbourhood.

These are small actions individually, but if all of us join in, the combined effect may be great.

*Margie Beautrais is the Educator at Whanganui Regional Museum.