Preliminary February and early March temperatures are in, and it鈥檚 now abundantly clear: warming .

As of 3 March, it appears that average temperatures across the northern hemisphere breached 2掳C above pre-industrial levels for the first time in recorded history, and since human civilisation began thousands of years ago.

The 2掳C mark has (somewhat arbitrarily) as the point above which climate change may begin to become 鈥溾�� to humanity. It has now arrived 鈥� though very briefly and only in the northern hemisphere 鈥� much more quickly than anticipated. This is a milestone moment for our species. Climate change deserves our greatest possible attention.

As for the planet as a whole, there are dozens of global temperature datasets, and usually I (and other climate journalists) wait until are released to announce a record-breaking month at the global level. But February鈥檚 global data is so extraordinary that there is no need to wait: it obliterated the all-time temperature record .

Using unofficial data and adjusting for different baseline temperatures, it appears that February was somewhere between 掳C and warmer than the long-term average, and about 0.2掳C above January 鈥� making it the most above-average month ever measured. (Since the globe had already warmed by about 0.45掳C above pre-industrial levels during the 1981-2010 baseline meteorologists commonly use, that amount has been added to the data.)

Stunning rise

Keep in mind that it took from the dawn of the industrial age 2015 to reach the first 1.0掳C rise. That means we have come as much as an extra 0.4掳C further in just the last five months. Even accounting for the margin of error associated with these preliminary datasets, that means it is virtually certain that February beat the record set in January for the most anomalously warm month for the entire globe ever recorded. That鈥檚 stunning.

It also means that for many parts of the northern hemisphere, there basically wasn鈥檛 a winter. Parts of the Arctic were more than 16掳C warmer than average for February, bringing them a few degrees above freezing, on par with typical June temperatures, in what is often the coldest month of the year.

In the US, the winter was in cities coast to coast. In Europe and Asia, dozens of countries their all-time temperature records for February. In the tropics, the record-warmth is prolonging the .

The northernmost permanent settlement, Norway鈥檚 Svalbard archipelago, 10掳C above what is usual in winter, with temperatures rising above freezing on 21 days since 1 December. That kind of extremely unusual weather has prompted a , especially in the Barents Sea.

Sceptical converts

The data for February is so overwhelming that even prominent climate change sceptics have embraced the record. Writing , former NASA scientist Roy Spencer said that according to satellite records 鈥� the dataset of choice by climate sceptics 鈥� February 听featured 鈥渨hopping鈥� temperature anomalies, especially in the Arctic.

Spurred by disbelief, Spencer checked his data with others and said the overlap is 鈥渁bout as good as it gets鈥�. Speaking with The Washington Post, the February data proves 鈥渢here has been warming. The question is how much warming there鈥檚 been.鈥�

Of course, all this is happening in the context of , which tends to boost global temperatures for beyond its usual peak at the end of the calendar year 鈥� mainly because it takes that long for excess heat to filter its way across the planet from the tropical Pacific Ocean.

But El Ni帽o isn鈥檛 entirely responsible for the absurd numbers we are seeing. Its influence on the Arctic and is probably small. In fact, is likely to be small 鈥� on the order of 0.1掳C or so.

No more normal

What鈥檚 actually happening now is the liberation of nearly two decades鈥� worth of global warming energy since the last major El Ni帽o in 1998.

Numbers like this amount to a step-change in our planet鈥檚 climate system. Peter Gleick, a climate scientist at the Pacific Institute in Oakland, California, said it is difficult to compare the current temperature spike: 鈥淭he old assumptions about what was normal are being tossed out the window鈥� The old normal is gone.鈥�

Almost overnight, the world has moved within arm鈥檚 reach of the climate goals negotiated . There, small island nations on the front line of climate change set a global temperature target of no more than 1.5掳C rise by the year 2100 as , and that limit was embraced by the global community.

On our current pace, we may reach that level for the first time 鈥� though briefly 鈥� later this year. In fact, for individual days, we are probably already there. We could now be in the heart of that could kick off with far-reaching implications on our species and the countless others we share the planet with.

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Defying a long-standing tradition of honeymoons in tropical locations, as well as the existence of the entire state of Texas, a new out this week from the US National Bureau of Economic Research claims there is a link between increasing temperatures and lower 鈥渃oital frequency鈥�.

Written in dry econometric prose, the report is sprinkled with profound insight into the possible implications of climate change on our sex lives, such as 鈥渢emperature may affect time use and, in turn, impact mixing rates among potential sexual partners鈥�.

A quick check of US birth rates and temperature by state shows that, overall, there鈥檚 probably not cause for alarm: Americans have the most sex in Alaska and Texas, the coldest and hottest states.

To be fair, this isn鈥檛 exactly what the researchers looked at. Instead of average temperature, they compared the frequency of unusual 鈥渉ot days鈥� (defined as warmer than 80 掳F or 27 掳C) 鈥� essentially heat waves 鈥� and the birth rate about nine months later, using 80 years of weather records and the birth dates of every American since 1931 to show a statistically significant link.

They then extrapolate that finding, using a climate change scenario, to project a 2.6 per cent decline in the US birth rate by 2100 鈥� equivalent to about 107,000 fewer births per year. But they鈥檙e very clear to state that this effect is less pronounced in places where it鈥檚 already commonly hot, like the southern US.

The study was first reported , quickly by Drudge, and also enthusiastically hot-taked by , , and a host of other media that don鈥檛 normally cover climate news. 惭补虫颈尘鈥檚 amazing was: 鈥淢other Nature: Just one Giant Cock Block.鈥� Unbelievably, New York 尘补驳补锄颈苍别鈥檚 was even better: 鈥淕lobal Warming Threatens Boners.鈥�

Though conservative media at the premise that weather can affect human behaviour, the study has a ring of truth. In a quick Twitter poll, I was able to replicate the scientists鈥� findings. I asked: Are you more or less likely to have sex if the temperature outside is above 80 掳F? Thirty-six per cent said more likely, 64 per cent less likely.

Love in a cold climate

that humans, like many other animals, have a seasonality in our birth rate that鈥檚 consistent across countries and cultures with similar climates. American babies are , though the peak is later in the year the further south you go (Washington state peaks in July and Florida peaks in October).

That implies Americans have more sex in the autumn and winter months. Researchers are still puzzled about exactly why this happens, but we know the effect is real. Public health experts have even taking advantage of the seasonality of births to maximize the effectiveness of vaccination campaigns.

However, there are a lot of problems with thinking about climate change in this way. For one thing, the authors make almost no effort to tease out complex socio-economic factors that contribute to seasonality in the birth rate, which have found is really important. Other factors, like (yes, I鈥檓 citing an Elle magazine article as evidence here) and , probably also play a big role.

Also, the effect the authors find is really, really small. Across 80 years of data, a single extra hot day produced a 0.4 per cent decrease in the birth rate, though the researchers found a slightly higher birth rate in the 11th, 12th, and 13th month after the hot day that makes up for about one-third of that drop (presumably, because couples trying to get pregnant had extra sex in the weeks following the heat wave).

An additional one-third of the drop was made up for by the rise of air conditioning since the 1970s. That means the effect of hot days on the birth rate in 2015 is probably only about 0.13 per cent 鈥� the researchers would probably find a bigger effect each time a new season of a popular show is released on Netflix.

Also, and most importantly, the researchers are clear that the evidence they find isn鈥檛 strong enough to prove there鈥檚 a link between it being hot outside and not so hot in the bedroom. In the authors鈥� own words, 鈥渢his positive relationship cannot be used to infer causal effects鈥�.

So, sleep (or don鈥檛 sleep) easy, friends. Yes, climate change will create across vast stretches of our planet, but less sex probably isn鈥檛 one of them.

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Eric Holthaus is a meteorologist who writes about weather and climate for Slate

Image credit: Spencer Platt/Getty

It is designed to speed up the retirement of coal-fired power plants 鈥� the most carbon-intensive way of generating electricity 鈥� and could the rate of their closures by 2040.

In a , Obama called the Clean Power Plan 鈥渢he biggest, most important step we鈥檝e ever taken to combat climate change鈥�. While that may be true, it鈥檚 not saying a whole heck of a lot.

As I wrote last year when the details were initially announced, many states to achieving the required reductions, thanks in part to a recent boom in cheap natural gas and the Obama administration鈥檚 choice of 2005 as the basis year for cuts, which was close to America鈥檚 all-time peak in carbon emissions. Obama鈥檚 plan is significant, but it鈥檚 not bold.

A previous version of the targets, announced last year, would have required states to begin implementing changes to their power-producing mix in 2020. The final version, to be announced today, gives states and utilities an extra two years. The targets will , depending on their current energy mix, and states will have flexible ways of achieving emissions reductions, including an option to join an interstate cap-and-trade scheme.

Business as usual

All this will be for some coal-intensive states, like Wyoming, but it鈥檚 being heralded as largely 鈥渂usiness as usual鈥� for some states, , that have already made significant efforts to shift their energy mix.

We can, and should, do much more. According to and 鈥� which helps keep world leaders honest in the run-up to this year鈥檚 international climate negotiations in Paris 鈥� the new provision puts America on a middling emissions-reduction pathway, at best.

It has been that the plan would shave just 6 per cent from US carbon emissions by 2030. Climate science and international equity by then. We鈥檙e nowhere near that pace.

Still, this plan is not nothing. In its coverage, The New York Times includes this hopeful gem: 鈥淏ut experts say that if the rules are combined with similar action from the world鈥檚 other major economies, as well as additional action by the next American president, emissions could level off enough to prevent the worst effects of climate change.鈥�

That鈥檚 a lot of hedging on which to base a climate legacy.

In fact, when compared with the climate plans of his would-be successors on the left 鈥� Hillary Clinton, Bernie Sanders and Martin O鈥橫alley 鈥� Obama鈥檚 in terms of ambition.

Kicking the can forward

Clinton, who has frequently with the president on climate, announced a preview of her own climate plan last week. It鈥檚 fractionally more ambitious than Obama鈥檚, but it essentially another few years.

And as Slate鈥荣 , there鈥檚 no guarantee the plan will endure in its current form after the president leaves office. Obama鈥檚 plan faces a phalanx of attacks , and legal challenges 鈥� which may take several years 鈥� to the Supreme Court.

Obama has any actions by a hostile Congress to weaken it, as long as he remains in office. It has been noted that the next president , so the ultimate fate of Obama鈥檚 climate legacy will be in the hands of others.

Doing all we can

In , Obama鈥檚 lead environmental advocate, Environmental Protection Agency administrator Gina McCarthy, said that if the rule moves forward, 鈥淲e鈥檒l know we鈥檙e doing all we can, together, to take action against climate change.鈥�

That鈥檚 simply not true. We can, and should, do much more.

Last week, former NASA climate scientist James Hansen, fresh off a , had harsh words for the slow, incremental progress that鈥檚 formed essentially the entirety of American鈥檚 climate ambition to date. 鈥淲e have two political parties, neither one of which is willing to face reality,鈥� Hansen . 鈥淐onservatives pretend it鈥檚 all a hoax, and liberals propose solutions that are non-solutions.鈥�

鈥淚t鈥檚 just plain silly,鈥� said Hansen, speaking specifically of Clinton鈥檚 planned renewable energy push. 鈥淣o, you cannot solve the problem without a fundamental change, and that means you have to make the price of fossil fuels honest.鈥�

In the end, our climate won鈥檛 care about how we fix this problem. But it鈥檚 clear that . If Obama truly wants to go all-in on climate change, he should meet Republicans where they are 鈥� as painful as that might be 鈥� and negotiate a way to pass a carbon tax. (I鈥檓 going to get a flood of email saying how na茂ve I am for saying that, but it鈥檚 true.)

Don鈥檛 get me wrong; the Clean Power Plan, if fully enacted as it is, would definitely help reduce our carbon emissions. But to imply that today鈥檚 nudge toward cleaner electricity will bring about a bold new era in American climate leadership is disingenuous. Growing economic headwinds in the fossil fuel sector 鈥� particularly in and 鈥� may bring about much sooner than Obama鈥檚 Clean Power Plan.

If Obama really wants to make a lasting impact on global warming, he can work or in Beijing, to work toward implementing a meaningful, economy-wide carbon tax as quickly as possible. Just because such a breakthrough feels impossible doesn鈥檛 mean it isn鈥檛 necessary.

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El Ni帽o is here, and this year鈥檚 version . Which is why investors might be wondering, given the forecast: how can I make some quick cash?

One of the clearest predictable outcomes of El Ni帽o is a , especially in the tropics where most agriculture is still rain fed and El Ni帽o鈥檚 weather-morphing power is strongest. That tends to make for less than ideal growing conditions for the major agricultural commodities there, including rice, cocoa, sugar, palm oil and coffee, leading to a . If one chooses to act on this information, farmers鈥� losses can be investors鈥� gains.

El Ni帽o鈥檚 weather extremes tend to happen in a roughly predictable pattern, which is exactly the kind of heads-up someone playing the market might be looking for.

Last week, Jodie Gunzberg, a commodities expert at S&P Dow Jones Indices, did of how well commodities investments perform in the 12 months following the onset of El Ni帽o conditions. Double-checking her numbers, I found that of the commodities indexes she listed 鈥� which include energy, metals, livestock and agriculture 鈥� only agriculture significantly outperforms the broader S&P 500 stock market index following an El Ni帽o.

During the year immediately following the past nine El Ni帽o events, the S&P 500 gained 16.5 per cent on average, while an investment in the S&P agricultural commodity index gained an average of 24.4 per cent 鈥� a relative windfall.

Odds on investment

Looking a bit deeper, though, there doesn鈥檛 appear to be much of a link between the strength of individual El Ni帽o events and increased return on investment: the three strongest of the past nine El Ni帽o episodes 鈥� 1983, 1998 and 2010 鈥� resulted in the year with the best agricultural index performance (2010) as well as the only two years with a negative return (1983 and 1998). So consider these correlations with caution. But the odds are that investing in agricultural commodities right now could fatten some bank accounts.

Here鈥檚 why. In India, Brazil and Indonesia 鈥� some of the world鈥檚 鈥� El Ni帽o usually means drought. The typical thanks to generally good growing conditions in the US usually isn鈥檛 enough to offset losses in other parts of the world, so a broad index of food prices tends to spike during El Ni帽o years. Hence some investors might buy up agricultural commodities early in the El Ni帽o cycle.

In India, things are starting to look especially bad. The country鈥檚 national weather service for this year鈥檚 critical monsoon rainfall on Tuesday 鈥� the last El Ni帽o, in 2009-10, resulted in one of the worst monsoon failures on record. Because of its importance to India鈥檚 economy, I have previously called the monsoon the .

India has hundreds of millions of farmers, most of whom don鈥檛 have access to irrigation 鈥� and hundreds of millions more who are dependent on stable food prices for their livelihood. Fearing a spike in inflation due to a possible El Ni帽o-induced drought, India鈥檚 central bank lowered interest rates again on Tuesday. The country鈥檚 minister for earth sciences, , gave some advice intended to quell fears of a weak economy: 鈥淟et鈥檚 pray to God that the revised forecast does not come true.鈥�

The last 12 months have seen the number of suicides among Indian . A on the tragic trend by BBC News cites the rash of extreme weather as a leading cause. For some people, that same weather will make them a killing.

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After months and months of , El Ni帽o has officially arrived, and it鈥檚 set to boost global warming to new record levels.

Climate scientists at the US National Oceanic and Atmospheric Administration (NOAA) reported the switch to official El Ni帽o status in their on Thursday, and outlined their decision process in .

Here鈥檚 what you need to know:

What is El Ni帽o, anyway?
El Ni帽o is one of the Earth鈥檚 most powerful climate signals, with the ability to shift weather patterns worldwide. It typically happens only two or three times a decade, and its most important feature is its predictability. Once in place, El Ni帽os normally linger for months, giving affected regions time to prepare for impacts.

Technically, for an official El Ni帽o episode, NOAA requires five consecutive three-month periods of abnormal warming of the so-called in the mid-tropical Pacific, about halfway between Indonesia and Peru. It usually takes a self-reinforcing link-up between the ocean and the atmosphere to achieve this, and it finally appears that the atmosphere is playing its part.

Is there anything special about this El Ni帽o?
El Ni帽o transfers huge amounts of heat from the oceans to the atmosphere, and there are hints that this El Ni帽o, combined with the already very warm global oceans, could bring about a new phase in global warming. An associated slow-moving indicator of Pacific Ocean temperatures, called the Pacific Decadal Oscillation (PDO), in December and January. A persistently strong PDO is associated with cold winters in the eastern US and drought in California 鈥� we鈥檝e had both in abundance this year.

Should the PDO stay strong, it will essentially join forces with El Ni帽o and increase the odds that 2015 will rank as the warmest year on record globally. Last autumn, I wrote that a PDO signal like we鈥檙e currently seeing could kick off over the next five to 10 years.

What does El Ni帽o mean for me?
The 2015 El Ni帽o could bring a , although NOAA cautions that it鈥檚 still pretty weak at this point so not much will immediately change.

In the US, typical springtime impacts of El Ni帽o point toward wetter-than-normal conditions in California, the south-east and the east coast. El Ni帽o years are also associated with heavy snowfall in the north-east, which we鈥檝e already.

鈥淭his El Ni帽o is likely too late and too weak to provide much relief for drought-stricken California,鈥� NOAA鈥檚 Mike Halpert, one of the agency鈥檚 official El Ni帽o forecasters, said . Florida, on the other hand, has the strongest signal for short-term impacts 鈥� the next few months will likely be very rainy in the Sunshine State.

Why now?
In a , the International Research Institute for Climate and Society鈥檚 Tony Barnston, who helped make the decision official, explained that the slow build-up of warm water in the Pacific over the past several months has made it 鈥渁 very unusual time to give an advisory for an El Ni帽o鈥�. El Ni帽os usually start in mid-summer, not early spring. This year鈥檚 sluggish onset may be because this year鈥檚 El Ni帽o isn鈥檛 happening in the typical way.

Close followers of the thermodynamics of the tropical Pacific (you know who you are) will note that borderline El Ni帽o conditions have been around unofficially . Finally, in February, the trade winds began to weaken across a vast stretch of the Pacific, causing an accumulation of subsurface heating.

Forecasters now believe that the ocean and atmosphere have joined forces in such a way that further warming and shifts in global weather patterns are likely 鈥� and that was the key to declaring an official start to El Ni帽o on Thursday.

Steve Zebiak, a Columbia University climate scientist who helped issue the first successful prediction of El Ni帽o in 1985, says he鈥檚 never seen anything like the run-up to the current El Ni帽o.

鈥淭here definitely are some questions here,鈥� Zebiak told me in a phone interview. For a while, Zebiak says, the run-up to this El Ni帽o was looking like that first successfully predicted event. In the last few months, though, things have changed. 鈥淣ow we鈥檙e in a situation where I can鈥檛 think of a good analogue for this entire past 12 months over many decades,鈥� Zebiak said. He thinks climate change may be shifting where El Ni帽o forms 鈥� now closer to the central Pacific rather than near South America. The impacts of this shift aren鈥檛 yet fully understood, but this year will provide a great chance for further study.

What鈥檚 next?
Typical El Ni帽os last only for six or eight months, but we could be in for a long one this time, spanning parts of two years or more. By later this year, if forecasts hold, global temperatures should soar to new records, according to Zebiak. A consensus of dynamic climate models now shows a until late summer, although the reliability of the forecast models 鈥� which change throughout the year 鈥� is typically at its lowest right about now.

Still, Zebiak says that if this El Ni帽o advances across the Pacific as currently predicted, 2015 would likely be the warmest year ever measured globally.

This article was first published by . Eric Holthaus is a meteorologist who writes about weather and climate for Slate.