Tag Archives: global warming

In the path of a hurricane

Hurricanes are one of the planet’s most destructive natural weather phenomenons. With Hurricane Matthew currently making it’s way through the Caribbean, it’s important that communities adhere to local emergency services and action plans.

Hurricane Genesis

Hurricanes are very large storm whose birth originates in the tropical oceans. They rotate about a central axis commonly called ‘the eye’. The oceans are a massive source of heat energy. Variations in sea surface temperature result in pressure differences in the atmosphere which cause storms to build up.

Tropical storms are characterised by their geographic origins. Image: NASA

To be classified as a hurricane a storm must reach wind speeds of at least 74 miles per hour. The rotation of the Earth gives these storm their characteristic spiral shape. Cyclonic storms in the northern hemisphere rotate anticlockwise while those in the southern hemisphere rotate clockwise.


The main hazards from hurricanes are strong winds (up to 150 miles per hour for the very large storms) and high volumes of rain. Hurricane winds can uproot trees and destroy houses. Large amounts of rainfall in a short period of time can cause floods and rising groundwater tables.

The water-clogged landscape remains unstable, with increased risk of landslides and surface failures, for many years after a particularly large event. For example, there were increased number of landslides in Taiwan for 6 years after Cyclone Bhola.

Extensive damage after the 2005 hurricane Katrina. Total damage > $100 billion USD. Image: Mark Wolfe

Historically significant hurricanes

The effect hurricanes have on people’s lives is illustrated by the word hurricane itself; after the Caribbean god of evil, Hurrican. They are a devastating force of nature.

  • Cyclone Bhola (1970) is historically the worst event for deaths with reported numbers as high as 500,000 people dead, mostly in Bangladesh.
  • Hurricane Katrina, which struck the east coast of the U.S. in 2005 is the most costliest hurricane with overall damage exceeding $100 billion.
  • The 1979 Cyclone Tip was the most intense hurricane ever recorded with wind speeds around 190 miles per hour. It was also the largest hurricane with a diameter around 2,170 kilometres.
  • Hurricane Sandy (U.S. east coast, 2010) was an abnormally large event due to the fusion of a tropical hurricane and a winter storm. With rising temperatures due to global warming these hybrid-storms are expected to become more frequent.

What can we do?

Cyclone Mahasen hit Sri Lanka, Bangladesh and Burma last season in May and resulted in far less deaths than expected thanks to swift action from the local governments. This shows that rapid response can save lives.

Proper preparation and sufficient warning can save thousands of lives every year.

Houses with appropriate shelters (as in the U.S.) need to be built in hurricane prone regions. Proper training should be given from early school level onwards on the appropriate actions to take before and after such events: e.g. having enough clean drinking water, tinned food, spare batteries for lights, mobile phone chargers, first aid kits etc.

Have a rapid response system in place from the national governmental level to manage pre-event evacuation (if needed) and post disaster recovery.

There is no clear agreement on what sort of effects climate change and global warming will have on hurricanes. However most scientists agree that the change will be for the worse whether it is in the form of increased number of hurricanes each year, increased size of the hurricanes or changes to the length of the hurricane season .  We need to invest more into understanding the science behind these storms and the effects global warming will have on their magnitude and frequency of occurrence.

More information
[1] National Hurricane Centre
[2] George M. Dunnavan & John W. Dierks (1980). An Analysis of Super Typhoon Tip (October 1979), Joint Typhoon Warning Center,1980
[3] www.weather.com/maps/news/atlstorm18/gulfofmexicosatellite_large.html

Earth’s Changing Surface water

Scientists have used satellite observations to study how the distribution of land and water on the Earth’s surface has changed over the last 30 years.

They found that the Earth’s surface has gained 115,000 sq km of water of extra water bodies and 173,000 sq km of water has now become land. The study is published in Nature Climate Change.

The interactive Aqua Monitor was developed by the Deltares Research Institute in the Netherlands. It is the first global-scale tool that shows, with a 30 metre resolution, where water has been transformed into land and vice-versa.

New lakes – seen in blue – are appearing on the Tibetan Plateau. Image: Deltares Aqua Monitor

The largest increase in water has been on the Tibetan Plateau, where increased water from melting glaciers are creating huge new lakes.

A rise in the number of dams built over the last 30 years has also increased the number of inland water bodies. Using the satellite data, the team were able to identify previously unreported constructions in Myanmar and North Korea.

The Aral Sea, which lies between Kazakhstan and Uzbekistan, has seen the the greatest conversion of water into land. Formerly one of the four largest lakes in the world, the Aral Sea has been steadily shrinking since the 1960s after the rivers that fed it were diverted by Soviet irrigation projects.

The Aral Sea has almost completely dried out. Green here shows the area of water that has converted to land. Image: Deltares Aqua Monitor

There have also been striking changes along our coastlines. The largest coastal water to land change is the construction of Palm Island and adjacent islands along the coast of Dubai. Many countries have shaped and extended their coastlines by land reclamation, including almost the entire coastline of eastern China from the Yellow Sea all the way down to Hong Kong.

Big data at everyone’s fingertips
Universally-available analytics for big satellite data may have major implications for monitoring capacity. At the very local scale, members of the general public can now make assessments without expert assistance if their houses are threatened by coastal erosion. At the regional scale, countries can monitor their water body changes and assess flooding impacts and strategy for disaster risk reduction.

Jaap Kwadijk, the Deltares scientific director: “This has never been done before. So it is difficult to imagine all the new applications that will be made using this tool. But the tool can be used by everybody and so I am sure multiple applications will emerge in the next few years”.

Original Paper: http://www.nature.com/nclimate/journal/v6/n9/full/nclimate3111.html


Snow algae speeds up Arctic melting: Tiny creatures with a big impact

by Dr Stefanie Lutz

The enthusiastic skiers or snow hikers among you may have already experienced the red snow phenomenon, which is caused by tiny microorganisms – the snow algae. Often termed ‘watermelon snow’ because of its colour and scent, I would not recommend eating it though. All the algae need to thrive is sunlight and liquid water. That’s why they form massive blooms in the warm months in spring and summer. But too much sun is not good for them either. They produce their own ‘sunscreen’ in the form of red pigments (the so called carotenoids), that gives them their red colouration.

Greenland_Mittivakat glacier_Red snow_copyright LGB
Red snow algae sampled colelcted from the Mittivakat glacier in Greenland. Image copyright: Liane G. Benning

Red snow looks very pretty, but why should we care about these tiny organisms? Well, even the smallest organisms can have a large impact. The red coloration darkens snow and glacial surfaces. This decreases their so called albedo. The albedo determines how much sunlight is reflected back from a surface. White snow reflects more sunlight, whereas the darker red snow reflects less. Therefore more heat is retained, which causes more melting. It is the same effect that makes people choose white clothing in places with high sun exposure such as deserts. Black clothing would make the sun even more unbearable.

I was really lucky to work on this topic during my PhD at the University of Leeds. Together with my supervisor Liane G. Benning, we collected 40 samples from various places in the Arctic, ranging from Greenland to Iceland, Svalbard and Northern Sweden. We found that these algal communities are very similar in all studied places and over one melt season they reduce the albedo by an additional 13%. Calculating how much this equates in additional melting is not easy and will be addressed in our ongoing work.

A colony of red snow algae under the microscope. Image copyright: Stefanie Lutz

Our findings have been published in Nature Communications. Since the paper was published I have been approached by a many worried journalists who aske me what we should do against these dreadful algae. Well, we cannot and should not do anything against them. Snow algae are actually very important members of the natural food chain. Like plants, they do photosynthesis, and in doing so they fix atmospheric CO2 and transform it into organic carbon that can be used by other organisms. However, there is one thing that is worrying – and that is global warming, which may cause a ‘runaway effect’. Snow algae need liquid water to bloom, with rising temperatures more melting will increase the extent of the snow algae, which will further darken the glacial surfaces, causing more melting, and so on. So the only thing we can and should do is to reduce human-induced climate change.

We’ve just come back from gathering samples from the Greenland Ice Sheet, where a record-breaking ice melting enderway. As part of a big international, UK led team, we will further investigate the extent of these algae and their contribution to melting. At the moment climate models don’t consider the effect of algae on snow and ice melt, it is time to change that!

Dr Stefanie Lutz is a postdoctoral research associate at the GFZ Helholtz centre in Potsdam, Germany.

Plight of the Bangladeshi

Lying on the floodplains of the mighty Ganges, Brahmaputra and Meghna rivers Bangladesh is a rich, fertile land. These giant river systems meet in the centre of the country and flow together into the Bay of Bengal which, at over 1600km wide, is the largest delta in the world.

Rising Sea Level

Bangladesh is often cited as one of the countries that will be most negatively affected by rising sea levels from human induced climate change. Two thirds of the country lies less than 5m above of sea level. With vast regions to the south much less than a 1m above sea level. The Intergovernmental Panel on Climate Change (IPCC) claims that just 1m rise in sea level could directly expose nearly 14 million people and result in potentially 17% land loss in southern Bangladesh.


Most of the country receives on average more than 2.5m of rainfall a year, 80% of which falls in about 4 months during the peak monsoon season, resulting in large annual floods. The flood waters bring nutrient rich clays and silts from the high Himalayas and deposit them on the river floodplains. These rich soils produce bountiful harvests of rice and other crops. Unsurprisingly, farming is the most common profession.

A flooded street. Source: NASA

However floods, once welcomed by farmers and their families are now harbingers of disaster. Human induced climate change has resulted in more erratic monsoon weather patterns with often larger than normal volumes of water being delivered in shorter time intervals. The resulting floods have had devastating effects on the Bangladeshi people. In 2012 three large floods hit the country in swift succession between the months of July and September directly affecting more than 5 million people. These are now a common annual occurrence.


Bangladesh is also subject to annual tropical cyclones, storm surges and tornadoes. Some of the worst natural disasters in recorded history were results of cyclonic storms in the Bengal region. Among them, the 1970 Bhola cyclone which claimed over 500,000 lives! Worryingly new research into the impacts of climate change has shown that large cyclonic storms will become a more common occurrence in the years and decades to come.


The foothills of the great Himalayan mountain belt has historically been the location of many large earthquakes. Earthquakes in the continent tend to be more infrequent compared to regions such as Japan and California. However this makes them more unpredictable and often unexpected. But when one does occur it can result in significant ground shaking. The 1897 magnitude 8.1 and 1950 magnitude 8.7 Assam earthquakes were two of the biggest to hit the region in recent times. The current building stock in Bangladesh is poorly built and most are not built to withstand ground shaking in an earthquake. The collapse of poorly built buildings is the greatest hazard during an earthquake.

The Savar building collapse near Dhaka Bangladesh, which killed 1129 garment factory workers. Source: Wikimedia Commons

So what can we as earth scientists do?

Bangladesh has a population of over 160 million and among the highest population density of any country in the world. With the majority of the country built on river floodplains combined with widespread corruption and ignorance a large earthquake could quite possibly result in the greatest natural calamity to have ever hit the country!

Bangladesh needs to increase its resilience if its people are to survive the multitude of natural hazards they face. Earth scientists are well placed to understand the risks involved from these hazards and can play a key role in all aspects of building a resilient infrastructure.

Climate science research is ongoing and needs to continue to better understand the affect human induced climate is having and will have on the annual monsoon. This knowledge needs to be translated into rainfall variation and flooding potentials and communicated with the people who need this information. The socio-economic issues of a rising sea level needs to be addressed and plans put in place to allow big cities to efficiently absorb and cater for migrants moving away from hazard prone coastal regions. Hydro-geologists and geochemists are helping to find sustainable clean, arsenic free water sources for drinking and farming. Seismologists and earthquake scientists are working to better understand the seismic risk in the Himalayan foothills; produce more accurate hazard maps and importantly identify the active faults within the region.

These are to name but a few of the ways earth scientists can get involved. I believe it is our moral duty to translate the practical aspects of our science into real benefits for people.


More information:
[1] http://www.ipcc.ch/ipccreports/tar/wg2/index.phpidp=446
[2] http://www.guardian.co.uk/global-development/2013/jan/23/bangladesh-floods-harbingers-disaster
[3] http://reliefweb.int/disaster/fl-2012-000106bgd
[4] http://en.wikipedia.org/wiki/List_of_Bangladesh_tropical_cyclones
[5] http://en.banglapedia.org/index.php?title=Main_Page

Our impact on the Earth

Here’s an impressive and rather scary visual of our impact on the earth, via the World Economic Forum.

Farming in an uncertain climate

At least some increase in global temperatures over the next few decades is now generally accepted as inevitable. However due to the still not fully understood nature of our climate and the interplay between its complex feedback systems, models still do not agree on the magnitude of the changes expected on a regional scale. Therefore, policy makers have, more often than not, been avoiding the issue of addressing the climatic affects on future crop yields.

According to a United Nations report, in 2007 agriculture accounted for 45 per cent of the world’s labour force, or about 1.3 billion people. In low-income countries it was slightly higher at 55 per cent with the figure being closer to 66 per cent in many parts of Africa and Asia.

University of Leeds scientist Prof Andy Challinor and co-workers have been working on the issue of how farmers can adapt to a warming world. Case studies from Sri Lanka and Central America illustrate how a “no-regrets” adaptation approach can benefit farming communities regardless of the magnitude and timing of the warming itself.

Sujit Kumar Mondal and his wife Rupashi Mondal of Gopalgonj district in southern Bangladesh working in their floating garden. A no-regrets adaptation. @Peter Murim, IRIN
Sujit Kumar Mondal and his wife Rupashi Mondal in southern Bangladesh working in their floating garden. A no-regrets adaptation. @Peter Murim, IRIN

The “no-regrets” approach to climate adaptation basically starts off by analysing the capacity of socio-economic groups such as communities, industries or countries. Adaptations strategies are then proposed that are both economically and politically feasible over a range of possible climate scenarios.

Sri Lanka

Sri Lanka is a country heavily dependent on agriculture. Current climate model predictions for changes in annual precipitation vary in magnitude and even direction of change, i.e some predict increases in rainfall while others predict a drop for a range of emission scenarios.

Given such uncertain predictions the government of Sri Lanka took a pragmatic approach to climate adaptation. It took into account the current capacity of local farmers to implement cost effective, low risk responses to high vulnerability districts.

Strategies implemented include the restoration of ancient water storage tank systems to harvest rainwater during the wet season to be used later in the dry season, the development of sustainable groundwater usage, adoption of micro-irrigation technologies and waste water reuse. These “no-regrets” changes enable a more sustainable approach to farming for Sri Lanka’s farming communities.

Central America

Arabica coffee beans. Source: Malcolm Manners
Arabica coffee beans. Source: Malcolm Manners

In Nicaragua 14% of the gross domestic product comes from coffee exports. While coffea arabica is the main source of livelihood for many farmers it is a crop very sensitive to climatic conditions. It requires stable temperatures between 19-22 degrees Celsius and little variation in annual rainfall. This translates into only certain altitude bands being suitable for arabica plantations. In Nicaragua this band lies between 400-1400m above sea level while in Columbia it is 1200-1800m.

Most climate models for this region predict a temperature rise over the next few decades but the models do not agree on the magnitude of the increase. For example, a temperature increase of 2 degrees Celcius (one of the more optimistic estimates) would result in a 400m change in the elevation range of the crop, equivalent to a loss of two thirds of the current altitude range.

The “no-regrets” adaptation plan for this region involves a change to a different crop, one more favourable to increased temperatures. At lower elevations arabica can be replaced with cocoa which has a similar cash value and is better suited to the higher temperature conditions. At higher altitudes in regions newly becoming suitable to coffee plantations the environmental impacts of the crop is considered to be too harmful. The region in between must involve a dynamic approach where farmers respond to the changing climate by adjusting their agricultural practices. Incremental adaptations through greater shading and other management practices including diversification will be the appropriate response.

Feeding the future

Despite uncertainties in regional climate forecasts much progress can be made by focusing on what we do know. By assessing the current capacity of local governments and farmers simple adaptation strategies can be implemented that are flexible over a range of probable climate futures. It is clear that as our climate continues to warm the affects on agriculture will become increasingly visible. We must start embracing changes to our agricultural practices and adaptation strategies. With a world even now, under food shortages we cannot afford to remain indifferent.

“Climate projections will always have a degree of uncertainty, but we need to stop using uncertainty as a rationale for inaction,” says Dr Sonja Vermeulen, head of research at Climate Change, Agriculture and Food Security (CCAFS).

Further Reading:
[1] http://www.pnas.org/content/early/2013/05/14/1219441110.full.pdf
[2] http://www.aljazeera.com/indepth/opinion/2013/06/20136585711493753.html
[3] http://ccafs.cgiar.org/news/press-releases/new-report-identifies-regret-free-approaches-adapting-agriculture-climate-change
[4] http://www.irinnews.org/report/98230/call-for-no-regret-climate-adaptation-strategies
[5] http://news.nationalgeographic.com/news/2012/11/121108-climate-change-coffee-coffea-arabica-botanical-garden-science/

A love poem for the Earth #showthelove

Yesterday was National Poetry Day, so here are some celebrities reading a simple love sonnet. We can protect the planet we love!

“So long as men can breathe, or eyes can see,
So long lives this, and this gives life to thee.”
– Sonnet 18, William Shakespeare

Islamic scholars call for action on climate change

A declaration by Islamic scholars calls on global leaders to reduce greenhouse gas emissions and suggests that Muslims have a religious duty to tackle climate change.

The Islamic Declaration on Global Climate Change, drawn up by a group of academics, Muslim scholars and international environment policy experts, was announced recently at a symposium on Islam and climate change in Istanbul. It calls on the 1.6 billion Muslims around the world to phase out our reliance on fossil fuels and switch instead to clean energy from renewable sources.

The statements reiterates the now well documented rise in global average surface temperatures since the industrial revolution and attributes this increase to excessive burning of fossil fuels.

It states that:
“This current rate of climate change cannot be sustained, and the Earth’s fine equilibrium (mīzān) may soon be lost.”

The declaration laments the slow progress of international climate-change negotiations:
“It is alarming that in spite of all the warnings and predictions, the successor to the Kyoto Protocol which should have been in place by 2012, has been delayed.”

It calls on global leaders, who will be meeting in Paris this December, to come to an “equitable and binding conclusion” and commit to a 100 % renewable energy and/or a zero emissions strategy.

The Islamic declaration follows a similar call to action by Pope Francis in his encyclical Laudato Si’ in June this year.

“All the faiths are talking about climate change,” says David Shreeve (via Nature), environmental advisor to the Church of England’s Archbishop’s Council. “It’s great that the Muslims are putting out a declaration, because whatever your faith, it’s a great opportunity for the faiths to stand up and say we really are concerned about this.”

The declaration ends with a reminder to all Muslims of a verse in the Qur’an –

وَلاَ تَمْشِ فِي الأَرْضِ مَرَحًا إِنَّكَ لَن تَخْرِقَ الأَرْضَ وَلَن تَبْلُغَ الْجِبَالَ طُولاً

Do not strut arrogantly on the earth.
You will never split the earth apart
nor will you ever rival the mountains’ stature.
Qur’an 17: 37

Read the full declaration here: http://islamicclimatedeclaration.org/islamic-declaration-on-global-climate-change