carbon emissions – Cabot Institute for the Environment blog

Climate change is threatening Madagascar’s famous forests – our study shows how serious it is

Posted on January 20, 2023March 27, 2023 by amanda.woodman-hardy

Urgent action is needed to protect Madagascar’s forests.
Rijasolo/AFP via Getty Images

Global climate change doesn’t only cause the melting of polar ice caps, rising sea levels and extreme weather events. It also has a direct effect on many tropical habitats and the animals and plants that inhabit them. As fossil fuel emissions continue to drive climate change, large areas of land are forecast to become much hotter and drier by the end of this century.

Many ecosystems, including tropical forests, wetlands, swamps and mangroves, will be unable to cope with these extreme climatic conditions. It is highly likely that the extent and condition of these ecosystems will decline. They will become more like deserts and savanna.

The island nation of Madagascar is of particular concern when it comes to climate change. Of Madagascar’s animal species, 85% cannot be found elsewhere on Earth. Of its plant species, 82% are unique to the island. Although a global biodiversity hotspot, Madagascar has experienced the highest rates of deforestation anywhere in the world. Over 80% of its original forest cover has already been cleared by humans.

This has resulted in large population declines in many species. For example, many species of lemurs (Madagascar’s flagship group of animals) have undergone rapid population decline, and over 95% of lemur species are now classified as threatened on the International Union for Conservation of Nature (IUCN) Red List.

Drier conditions brought about by climate change have already resulted in widespread bush fires throughout Madagascar. Drought and famine are increasingly severe for the people living in the far south and south-western regions of the island.

Madagascar’s future will likely depend profoundly on how swiftly and comprehensively humans deal with the current climate crisis.

What we found

Our study investigated how future climate change is likely to affect four of Madagascar’s key forest habitat types. These four forest types are the dry deciduous forests of the west, humid evergreen forests of the east, spiny bush forests of the arid south, and transitional forests of the north-west corner of the island.

Using computer-based modelling, we simulated how each forest type would respond to climate change from the current period up to the year 2080. The model used the known distribution of each forest type, and current and future climatic data.

We did this under two different conditions: a mitigation scenario, assuming human reliance on greenhouse gas reduces according to climate commitments already made; and an unmitigated scenario, assuming greenhouse gas emissions continue to increase at their current rate.

Our results suggest that unmitigated climate change will result in declines of Madagascar’s forests. The area of land covered by humid forest, the most extensive of the four forest types, is predicted to decrease by about 5.66%. Dry forest and spiny bush are also predicted to decline in response to unmitigated climate change. Transitional forest may actually increase by as much as 5.24%, but this gain will almost certainly come at the expense of other forest types.

We expected our model to show that mitigating climate change would result in net forest gain. Surprisingly, our results suggest entirely the opposite. Forest occurrence will decrease by up to 5.84%, even with efforts to mitigate climate change. This is because global temperatures are forecast to increase under both mitigated and unmitigated scenarios.

These predicted declines are in addition to the huge losses of forest already caused by ongoing deforestation throughout the island.

It looks as if the damage has already been done.

Climate change, a major threat

The results of our research highlight that climate change is indeed a major threat to Madagascar’s forests and likely other ecosystems worldwide. These findings are deeply concerning for the survival of Madagascar’s animals and plants, many of which depend entirely on forest habitat.

Not only will climate change decrease the size of existing forests, changes in temperature and rainfall will also affect the amount of fruit that trees produce.

A Lemur on tree in the forest. — Madagascar lemurs and other animal and plant species may become extinct if the forests disappear.
Rijasolo/AFP

Many of Madagascar’s animals, such as its lemurs, rely heavily on fruit for food. Changes in fruit availability will have serious impact on the health, reproductive success and population growth of these animals. Some animals may be able to adapt to changes in climate and habitat, but others are very sensitive to such changes. They are unlikely to survive in a hot, arid environment.

This will also have serious knock-on effects for human populations that depend on forests and animals for eco-tourism income. Approximately 75% of Madagascar’s population depends on the forest and subsistence farming for survival, and the tourism sector contributes over US$600 million towards the island’s economy annually.

To ensure that Madagascar’s forests survive, immediate action is needed to end deforestation, protect the remaining patches of forest, replant and restore forests, and mitigate global carbon emissions. Otherwise these remarkable forests will eventually disappear, along with all the animals and plants that depend on them.

——————————

This blog is written by Daniel Hending, Postdoctoral Research Assistant Animal Vibration Lab, University of Oxford and Cabot Institute for the Environment member Marc Holderied, Professor in Sensory Biology, University of Bristol. This article is republished from The Conversation under a Creative Commons license. Read the original article.

Marc Holderied

Global carbon budget reveals dangerous footprints

Posted on November 20, 2013April 19, 2023 by janet.crompton

Carbon dioxide is the most important greenhouse gas produced by human activities, and one which is likely to cause significant global climate change if levels continue to increase at the current rates. This year’s Global Carbon Budget holds disappointing yet hardly unexpected news; in 2012, carbon dioxide (CO₂) emissions rose by 2.1% to the highest levels in human history, a total of 9.7 billion tonnes.

CDIAC Data; Le Quiere et al 2013. Global Carbon Project 2013. Data not adjusted for leap year.

The annual Carbon Budget report is compiled by the Global Carbon Project, a collaboration of 77 scientists from around the world including the Cabot Institute’s own Dr Jo House. They predict that in 2013, global carbon emissions will have increased by a further 2.1%, setting a new record high.

Major CO₂ emitters

China produced the most CO₂ in 2012 (27% of total), which was almost twice as much as the second worst offender, the USA (14%). The European Union (EU) contributed 10% of emissions. China’s emissions increased 5.9% between 2011 and 2012, whilst the USA and EU continued to decrease their CO₂ output (by 3.7% and 1.3% respectively).

CDIAC Data; Le Quiere et al 2013. Global Carbon Project 2013.

While developing nations like China and India have high levels of greenhouse gas emissions, it is important to note that per capita the USA has by far the highest emission rate at 4.4 tonnes of carbon per person per year (tC/p/yr). China has reached EU levels of 1.9 tC/p/yr, while India produces just 0.5tC/p/yr. Since the Industrial Revolution the USA and Europe still have the highest cumulative output of CO₂ from burning fossil fuels, something to consider before we become too self-righteous.

CDIAC Data; Le Quiere et al 2013. Global Carbon Project 2013.

Carbon sinks

Image by Manfred Heyde

Increased CO₂ emissions are absorbed by carbon sinks, specifically the atmosphere, the oceans and the land. On land, trees and other plants absorb around 27% of emitted CO₂ for photosynthesis, which results in more growth and eventually more carbon stored as leaf litter in the soil.

In the oceans, algae may absorb some CO₂ for photosynthesis (although not as much as was once hoped), but the water itself absorbs most of the 27% of CO₂ stored in the oceans. Unfortunately when carbon dioxide dissolves in water it can react to form carbonic acid, a leading cause of ocean acidification. Since the Industrial Revolution, oceans have become approximately 30% more acidic. If present trends continue, oceans will be 170% more acidic by 2100, a devastating change for shellfish and corals which rely on an alkaline calcium carbonate exoskeleton, and the other marine life that depend on these species.

The atmosphere absorbs the remaining 45% of CO₂ emissions. Over the past 250 years the atmospheric CO₂ concentration has risen from 227 parts per million (ppm) to an average of 393ppm in 2012. Back in May, the first CO2 reading of 400ppm was recorded, a significant milestone in the relentlessly increasing greenhouse gas levels. We are now on track to see a ‘likely’ 3.2-5.4°C increase in global temperature by 2100, causing severe droughts and desertification of agricultural land around the world and flooding of low lying coastal areas.

The Kyoto protocol

In 1992, 37 industrialised countries agreed to reduce their carbon dioxide emissions by an average of 5% below 1990 levels during the period of 2008 to 2012. The Global Carbon Budget reported that whilst some regions such as Europe did reduce their CO₂ output, other areas (eg. Asia, Africa, Middle East) doubled or even tripled their emissions, resulting in a net gain of 58% more CO₂ emissions in 2012 than in 1990.

The biggest CO₂ emitter, China, recently joined almost 200 other countries in agreeing to sign the pledge to reduce their carbon emissions at a summit in Paris in 2015. It is hoped that this climate change summit will follow on from the work started by the Kyoto protocol to reduce CO₂ emissions to a more sustainable level.

What’s your carbon footprint?

We are at a critical stage in history. The Global Carbon Budget suggests that we have already produced 70% of the carbon dioxide it is possible to emit without causing a significant and irreversible change to the planet’s climate. It is vital that all nations work together to reduce carbon emissions to a sustainable level, preventing a 2°C increase in global temperature.

If you would like to calculate your carbon footprint, visit the government’s carbon calculator.

This blog is written by Sarah Jose, Biological Sciences, University of Bristol

You can follow Sarah on Twitter @JoseSci

Sarah Jose

All Party Parliamentary Climate Change Group – decarbonisation targets

Posted on March 5, 2013April 20, 2023 by janet.crompton

This month’s All Party Parliamentary Climate Change Group (APPCCG) meeting centred on the age old problem of setting decarbonisation targets; the question being, are they useful milestones, or millstones around the necks of the energy industry.

David Kennedy, CCC

Joining the discussion at the meeting were several senior figures in the field, including David Kennedy, chief executive of the Committee on Climate Change (CCC), and until recently a frontrunner for the top civil service job at the Department of Energy and Climate Change (DECC). Mr. Kennedy’s appearance at this meeting comes on the heels of an open letter presented by his organisation to Ed Davey, the minister at DECC, urging swifter action on establishing carbon intensity targets. Mr. Kennedy explained his concern that lingering doubt over whether legislative targets will be set dissuades investors in renewable energy technologies, and ultimately hampers efforts to decarbonise the electricity market.

It’s worth noting that the UK already has binding targets for reducing carbon emissions; indeed, it was the very first country to enact such legislation. However, these targets will ultimately be assessed only in 2050, which on the political timescale is several lifetimes away. Further, the 2008 Energy Act that carries this legislation allows successive governments to exceed carbon emission budgets in the short run, so long as they reduce future budgets accordingly. Without intervening milestones between now and 2050, one can certainly see an incentive for incumbent governments to neglect decarbonisation- procrastination on a national scale.

Opposing this view was David Hone, the climate change advisor for Shell. Mr. Hone explained that UK energy policy should not be viewed as a closed system- indeed, our policy is linked directly to those of our European partners though EU-ETS, the European Union Emissions Trading Scheme. His view was that by enacting further legislation, the government would be unfairly constricting energy producers in the UK. Further, any emissions savings made in the UK could be offset by additional emissions in Europe, as the EU-ETS would simply sell emissions rights elsewhere.

Guy Newey, Policy Exchange

Another significant contribution was made by Guy Newey, Head of Environment and Energy at the think tank Policy Exchange. While Mr. Newey agreed in principle with the idea of bringing forward decisions on decarbonisation targets to 2014, he also made the point that uncertainty on this topic was a significant disincentive to investors, and that a quick and firm resolution to this question was essential; to that end, he could live with an imperfect answer.

This blog is written by Neeraj Oak, University of Bristol

Neeraj Oak