Hurricanes Irma and Harvey have reignited discussions about link between global warming and extreme weather, with climate scientists now saying they can show the connections between the two phenomena better than ever before.

“A warmer ocean makes a warmer atmosphere, a warmer atmosphere can hold more moisture,” says Gabriel Vecchi, a professor of geosciences at Princeton University who studies extreme weather events. “So, all other things equal, the same storm in a warmer planet would give you more rainfall.”

In a warming world the vapour capacity of the atmosphere increases, and more extreme rainfall, like Texas is witnessing right now, is to be expected as a result. This leads many to conclude that climate change exacerbated the impacts of hurricane Harvey.

It is very appropriate to highlight that this is the kind of event we expect to see more of in a warming world. However, to apply this argument directly and attribute (and quantify) the impacts from Harvey itself to human-induced climate change, neglects that climate change is not just about warming.

In a changing climate, two effects come together: not only does the atmosphere warm up (thermodynamic effect) but the atmospheric circulation, which determine where, when, and how weather systems develop, can change as well (dynamic effect).

Dynamical factors and thermodynamic aspects of climate change can interact in complex ways and there are many examples where the circulation is as important as the thermodynamics.

Hence, while it is very likely that climate changes played a role in the intensity of the rainfall, it is far from straightforward in practice to quantify this role. As such, determining the role of climate change in increasing or decreasing the present and future likelihood of a rain storm like Harvey presents a challenge.


Financial distress, lack of timely help and crop failure has often been blamed for the spiraling numbers in farm suicides in India. Now, a US study has added climate change as another significant factor that is driving the disaster northwards.

Climate change may have contributed to the suicides of nearly 60,000 Indian farmers and farm workers over the past three decades, according to new research that examines the toll rising temperatures are already taking on vulnerable societies.

It’s a widespread and intensely personal issue, one that has been difficult to tease out the root source. Debt, mental health, lack of social services, weather vagaries and even media coverage have all been put forward as part of the problem. Now, recent research published in the Proceedings of the National Academy of Sciences suggests that climate change could also be playing a role.

Just a degree rise in temperatures above 20 degrees during the crucial crop growing season (June-September) could push up the number of suicides by 70. In the last 30 years, a total of 59,000 farmer suicides in India have been attributed to the direct cause of rising temperatures by the study published by the University of California, Berkeley researchers.

The striking correlation between the rising temperatures — dropping yields — suicides established by the researchers in the 13 States studied (1956-2000) is both disturbing and could be critical in formulating preventive strategies in future. Maharashtra (especially Vidarbha region), Telangana, Karnataka, Andhra Pradesh and Tamil Nadu clearly demonstrate that when temperatures rise, crop yields drop and higher numbers of suicides are reported.

Because of climate change, India is only going to get hotter. Starting in 2014, each subsequent year has shattered the previous year’s record as the hottest ever. Scientific consensus predicts average global temperatures to rise as much as 3°C by 2050. Carleton says that interventions have been either wholly absent or woefully insufficient over the period of time her study covers, and without an increase in measures like subsidized crop insurance, worker retraining, or low-cost loans available to farmers to keep them afloat when harvests suffer, India is looking down the barrel of more frequent hardship and, sadly, more lives lost to self-harm.

The authors say the relationship between economic shocks and suicide is controversial and, in India, the effect of income-damaging climate variation on suicide rates is unknown. Though, the Centre has announced a $1.3 billion climate-based, crop insurance scheme motivated as suicide prevention policy, evidence to support such an intervention is still lacking. Previous studies of income variability affecting suicide are mostly anecdotal or qualitative and do not attempt to identify and synthesize quantitative relationships between climates, crops and suicides, they claimed.

Farm loan write-offs by Andhra Pradesh, Telangana, Uttar Pradesh recently and even by the UPA government have been resorted to as means to alleviate the problems, help farmers distress and in a way gain political mileage. Even subsidies on inputs like fertilizers and easy loans have not halted the growing demands from farmers for more soft loans and better minimum support price for the crop.

With Indian agriculture continuing to be dependent on timely rains, landholdings being small and farmers struggling for finances, the challenge to face the consequences of the growing impact of climate change is indeed daunting. Forecasts predict a temperature rise of at least 3 more degrees by 2050.

This implies urgent and increased measures to improve rural farmer’s credit, crop insurance cover and preventive strategies both at policy and ground level to avoid disastrous consequences in the long-term.


According to the United Nations Population Fund, human population grew from 1.6 billion to 6.1 billion people during the course of the 20th century. (Think about it: It took all of time for population to reach 1.6 billion; then it shot to 6.1 billion over just 100 years.) During that time emissions of CO2, the leading greenhouse gas, grew 12-fold. And with worldwide population expected to surpass nine billion over the next 50 years, environmentalists and others are worried about the ability of the planet to withstand the added load of greenhouse gases entering the atmosphere and wreaking havoc on ecosystems down below.

In 1970, when worldwide greenhouse gas emissions had just begun to transgress the sustainable capacity of the atmosphere, the world population was about 3.7 billion; today it’s about 6.1 billion — an increase of 86 percent.

In that same period, worldwide emissions from fossil fuels rose from about 14 billion tons to an estimated 29 billion tons — an increase of 107 percent.

Population growth is not the direct cause of global warming, burning fossil fuels is.

Where some of the confusion comes from is that CO2 emissions are reasonably well correlated to population.

It’s not a one-to-one relationship, but there is a solid relationship. For a couple of centuries, more people meant a great deal more CO2 which more closely tracked gross domestic product on a one-to-one ratio. As countries became richer, that was reflected in their GDP and also in their reduction in fertility. More GDP equals flattening population but still increasing CO2 emissions.

“Population, global warming and consumption patterns are inextricably linked in their collective global environmental impact,” reports the Global Population and Environment Program at the non-profit Sierra Club. “As developing countries’ contribution to global emissions grows, population size and growth rates will become significant factors in magnifying the impacts of global warming.”

According to the Worldwatch Institute, a nonprofit environmental think tank, the overriding challenges facing our global civilization are to curtail climate change and slow population growth. “Success on these two fronts would make other challenges, such as reversing the deforestation of Earth, stabilizing water tables, and protecting plant and animal diversity, much more manageable,” reports the group. “If we cannot stabilize climate and we cannot stabilize population, there is not an ecosystem on Earth that we can save.”

Many population experts believe the answer lies in improving the health of women and children in developing nations. By reducing poverty and infant mortality, increasing women’s and girls’ access to basic human rights (health care, education, economic opportunity), educating women about birth control options and ensuring access to voluntary family planning services, women will choose to limit family size.




Global climate change has already had observable effects on the environment. Glaciers have shrunk, ice on rivers and lakes is breaking up earlier, plant and animal ranges have shifted and trees are flowering sooner.

Effects that scientists had predicted in the past would result from global climate change are now occurring: loss of sea ice, accelerated sea level rise and longer, more intense heat waves.

Scientists have high confidence that global temperatures will continue to rise for decades to come, largely due to greenhouse gases produced by human activities. The Intergovernmental Panel on Climate Change (IPCC), which includes more than 1,300 scientists from the United States and other countries, forecasts a temperature rise of 2.5 to 10 degrees Fahrenheit over the next century.

According to the IPCC, the extent of climate change effects on individual regions will vary over time and with the ability of different societal and environmental systems to mitigate or adapt to change.

The IPCC predicts that increases in global mean temperature of less than 1.8 to 5.4 degrees Fahrenheit (1 to 3 degrees Celsius) above 1990 levels will produce beneficial impacts in some regions and harmful ones in others. Net annual costs will increase over time as global temperatures increase.

“Taken as a whole,” the IPCC states, “the range of published evidence indicates that the net damage costs of climate change are likely to be significant and to increase over time.”

Dirtier air

Rising temperatures also worsen air pollution by increasing ground level ozone, which is created when pollution from cars, factories, and other sources react to sunlight and heat. Ground-level ozone is the main component of smog, and the hotter things get, the more of it we have. Dirtier air is linked to higher hospital admission rates and higher death rates for asthmatics. It worsens the health of people suffering from cardiac or pulmonary disease. And warmer temperatures also significantly increase airborne pollen, which is bad news for those who suffer from hay fever and other allergies.

Higher wildlife extinction rates

As humans, we face a host of challenges, but we’re certainly not the only ones catching heat. As land and sea undergo rapid changes, the animals that inhabit them are doomed to disappear if they don’t adapt quickly enough. Some will make it, and some won’t. According to the Intergovernmental Panel on Climate Change’s 2014 assessment, many land, freshwater, and ocean species are shifting their geographic ranges to cooler climes or higher altitudes, in an attempt to escape warming. They’re changing seasonal behaviors and traditional migration patterns, too. And yet many still face “increased extinction risk due to climate change.” Indeed, a 2015 study showed that vertebrate species—animals with backbones, like fish, birds, mammals, amphibians, and reptiles—are disappearing 114 times faster than they should be, a phenomenon that has been linked to climate change, pollution, and deforestation.

More acidic oceans

The earth’s marine ecosystems are under pressure as a result of climate change. Oceans are becoming more acidic, due in large part to their absorption of some of our excess emissions. As this acidification accelerates, it poses a serious threat to underwater life, particularly creatures with calcium carbonate shells or skeletons, including mollusks, crabs, and corals. This can have a huge impact on shell-fisheries. Indeed, as of 2015, acidification is believed to have cost the Pacific Northwest oyster industry nearly $110 million. Coastal communities in 15 states that depend on the $1 billion nationwide annual harvest of oysters, clams, and other shelled mollusks face similar long-term economic risks.

Higher sea levels

The Polar Regions are particularly vulnerable to a warming atmosphere. Average temperatures in the Arctic are rising twice as fast as they are elsewhere on earth, and the world’s ice sheets are melting fast. This not only has grave consequences for the region’s people, wildlife, and plants; its most serious impact may be on rising sea levels. By 2100, it’s estimated our oceans will be one to four feet higher, threatening coastal systems and low-lying areas, including entire island nations and the world’s largest cities, including New York, Los Angeles, and Miami as well as Mumbai, Sydney, and Rio de Janeiro.


Climate Change isn’t the only consequence of carbon pollution from fossil fuels. If driving global temperature rise wasn’t enough, increased carbon in our atmosphere is also behind the rapid acidification of our world’s oceans.

But what exactly is ocean acidification?

When carbon dioxide (CO2) is absorbed by seawater, chemical reactions occur that reduce seawater pH, carbonate ion concentration, and saturation states of biologically important calcium carbonate minerals. These chemical reactions are termed “Ocean Acidification” or “OA” for short.

Oceans becoming more acidic after the Industrial Revolution are no accident. As humans burn more and more fossil fuels, the concentration of carbon dioxide in our atmosphere continues to rise, driving climate change and making both air and sea temperatures hotter and hotter.

Ocean acidification is expected to impact ocean species to varying degrees. Photosynthetic algae and sea grasses may benefit from higher CO2 conditions in the ocean, as they require CO2 to live just like plants on land. On the other hand, studies have shown that a more acidic environment has a dramatic effect on some calcifying species, including oysters, clams, sea urchins, shallow water corals, deep sea corals, and calcareous plankton. When shelled organisms are at risk, the entire food web may also be at risk. Today, more than a billion people worldwide rely on food from the ocean as their primary source of protein. Many jobs and economies in the U.S. and around the world depend on the fish and shellfish in our oceans.

Ocean acidification is an emerging global problem. Over the last decade, there has been much focus in the ocean science community on studying the potential impacts of ocean acidification. Since sustained efforts to monitor ocean acidification worldwide are only beginning, it is currently impossible to predict exactly how ocean acidification impacts will cascade throughout the marine food chain and affect the overall structure of marine ecosystems. With the pace of ocean acidification accelerating, scientists, resource managers, and policymakers recognize the urgent need to strengthen the science as a basis for sound decision making and action.

Future predictions indicate that the oceans will continue to absorb carbon dioxide and become even more acidic. Estimates of future carbon dioxide levels, based on business as usual emission scenarios, indicate that by the end of this century the surface waters of the ocean could be nearly 150 percent more acidic, resulting in a pH that the oceans haven’t experienced for more than 20 million years.